1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
12 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
13 html_root_url = "https://doc.rust-lang.org/nightly/")]
15 #![feature(crate_visibility_modifier)]
16 #![cfg_attr(not(stage0), feature(nll))]
17 #![feature(rustc_diagnostic_macros)]
18 #![feature(slice_sort_by_cached_key)]
24 extern crate syntax_pos;
25 extern crate rustc_errors as errors;
29 extern crate rustc_data_structures;
30 extern crate rustc_metadata;
32 pub use rustc::hir::def::{Namespace, PerNS};
34 use self::TypeParameters::*;
37 use rustc::hir::map::{Definitions, DefCollector};
38 use rustc::hir::{self, PrimTy, Bool, Char, Float, Int, Uint, Str};
39 use rustc::middle::cstore::CrateStore;
40 use rustc::session::Session;
42 use rustc::hir::def::*;
43 use rustc::hir::def::Namespace::*;
44 use rustc::hir::def_id::{CRATE_DEF_INDEX, LOCAL_CRATE, DefId};
46 use rustc::hir::{Freevar, FreevarMap, TraitCandidate, TraitMap, GlobMap};
47 use rustc::util::nodemap::{NodeMap, NodeSet, FxHashMap, FxHashSet, DefIdMap};
49 use rustc_metadata::creader::CrateLoader;
50 use rustc_metadata::cstore::CStore;
52 use syntax::source_map::SourceMap;
53 use syntax::ext::hygiene::{Mark, Transparency, SyntaxContext};
54 use syntax::ast::{self, Name, NodeId, Ident, FloatTy, IntTy, UintTy};
55 use syntax::ext::base::SyntaxExtension;
56 use syntax::ext::base::Determinacy::{self, Determined, Undetermined};
57 use syntax::ext::base::MacroKind;
58 use syntax::symbol::{Symbol, keywords};
59 use syntax::util::lev_distance::find_best_match_for_name;
61 use syntax::visit::{self, FnKind, Visitor};
63 use syntax::ast::{CRATE_NODE_ID, Arm, IsAsync, BindingMode, Block, Crate, Expr, ExprKind};
64 use syntax::ast::{FnDecl, ForeignItem, ForeignItemKind, GenericParamKind, Generics};
65 use syntax::ast::{Item, ItemKind, ImplItem, ImplItemKind};
66 use syntax::ast::{Label, Local, Mutability, Pat, PatKind, Path};
67 use syntax::ast::{QSelf, TraitItemKind, TraitRef, Ty, TyKind};
70 use syntax_pos::{Span, DUMMY_SP, MultiSpan};
71 use errors::{Applicability, DiagnosticBuilder, DiagnosticId};
73 use std::cell::{Cell, RefCell};
75 use std::collections::BTreeSet;
78 use std::mem::replace;
79 use rustc_data_structures::sync::Lrc;
81 use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
82 use macros::{InvocationData, LegacyBinding, ParentScope};
84 // NB: This module needs to be declared first so diagnostics are
85 // registered before they are used.
90 mod build_reduced_graph;
93 fn is_known_tool(name: Name) -> bool {
94 ["clippy", "rustfmt"].contains(&&*name.as_str())
97 /// A free importable items suggested in case of resolution failure.
98 struct ImportSuggestion {
102 /// A field or associated item from self type suggested in case of resolution failure.
103 enum AssocSuggestion {
110 struct BindingError {
112 origin: BTreeSet<Span>,
113 target: BTreeSet<Span>,
116 impl PartialOrd for BindingError {
117 fn partial_cmp(&self, other: &BindingError) -> Option<cmp::Ordering> {
118 Some(self.cmp(other))
122 impl PartialEq for BindingError {
123 fn eq(&self, other: &BindingError) -> bool {
124 self.name == other.name
128 impl Ord for BindingError {
129 fn cmp(&self, other: &BindingError) -> cmp::Ordering {
130 self.name.cmp(&other.name)
134 enum ResolutionError<'a> {
135 /// error E0401: can't use type parameters from outer function
136 TypeParametersFromOuterFunction(Def),
137 /// error E0403: the name is already used for a type parameter in this type parameter list
138 NameAlreadyUsedInTypeParameterList(Name, &'a Span),
139 /// error E0407: method is not a member of trait
140 MethodNotMemberOfTrait(Name, &'a str),
141 /// error E0437: type is not a member of trait
142 TypeNotMemberOfTrait(Name, &'a str),
143 /// error E0438: const is not a member of trait
144 ConstNotMemberOfTrait(Name, &'a str),
145 /// error E0408: variable `{}` is not bound in all patterns
146 VariableNotBoundInPattern(&'a BindingError),
147 /// error E0409: variable `{}` is bound in inconsistent ways within the same match arm
148 VariableBoundWithDifferentMode(Name, Span),
149 /// error E0415: identifier is bound more than once in this parameter list
150 IdentifierBoundMoreThanOnceInParameterList(&'a str),
151 /// error E0416: identifier is bound more than once in the same pattern
152 IdentifierBoundMoreThanOnceInSamePattern(&'a str),
153 /// error E0426: use of undeclared label
154 UndeclaredLabel(&'a str, Option<Name>),
155 /// error E0429: `self` imports are only allowed within a { } list
156 SelfImportsOnlyAllowedWithin,
157 /// error E0430: `self` import can only appear once in the list
158 SelfImportCanOnlyAppearOnceInTheList,
159 /// error E0431: `self` import can only appear in an import list with a non-empty prefix
160 SelfImportOnlyInImportListWithNonEmptyPrefix,
161 /// error E0433: failed to resolve
162 FailedToResolve(&'a str),
163 /// error E0434: can't capture dynamic environment in a fn item
164 CannotCaptureDynamicEnvironmentInFnItem,
165 /// error E0435: attempt to use a non-constant value in a constant
166 AttemptToUseNonConstantValueInConstant,
167 /// error E0530: X bindings cannot shadow Ys
168 BindingShadowsSomethingUnacceptable(&'a str, Name, &'a NameBinding<'a>),
169 /// error E0128: type parameters with a default cannot use forward declared identifiers
170 ForwardDeclaredTyParam,
173 /// Combines an error with provided span and emits it
175 /// This takes the error provided, combines it with the span and any additional spans inside the
176 /// error and emits it.
177 fn resolve_error<'sess, 'a>(resolver: &'sess Resolver,
179 resolution_error: ResolutionError<'a>) {
180 resolve_struct_error(resolver, span, resolution_error).emit();
183 fn resolve_struct_error<'sess, 'a>(resolver: &'sess Resolver,
185 resolution_error: ResolutionError<'a>)
186 -> DiagnosticBuilder<'sess> {
187 match resolution_error {
188 ResolutionError::TypeParametersFromOuterFunction(outer_def) => {
189 let mut err = struct_span_err!(resolver.session,
192 "can't use type parameters from outer function");
193 err.span_label(span, "use of type variable from outer function");
195 let cm = resolver.session.source_map();
197 Def::SelfTy(maybe_trait_defid, maybe_impl_defid) => {
198 if let Some(impl_span) = maybe_impl_defid.and_then(|def_id| {
199 resolver.definitions.opt_span(def_id)
202 reduce_impl_span_to_impl_keyword(cm, impl_span),
203 "`Self` type implicitly declared here, by this `impl`",
206 match (maybe_trait_defid, maybe_impl_defid) {
208 err.span_label(span, "can't use `Self` here");
211 err.span_label(span, "use a type here instead");
213 (None, None) => bug!("`impl` without trait nor type?"),
217 Def::TyParam(typaram_defid) => {
218 if let Some(typaram_span) = resolver.definitions.opt_span(typaram_defid) {
219 err.span_label(typaram_span, "type variable from outer function");
223 bug!("TypeParametersFromOuterFunction should only be used with Def::SelfTy or \
228 // Try to retrieve the span of the function signature and generate a new message with
229 // a local type parameter
230 let sugg_msg = "try using a local type parameter instead";
231 if let Some((sugg_span, new_snippet)) = cm.generate_local_type_param_snippet(span) {
232 // Suggest the modification to the user
233 err.span_suggestion_with_applicability(
237 Applicability::MachineApplicable,
239 } else if let Some(sp) = cm.generate_fn_name_span(span) {
240 err.span_label(sp, "try adding a local type parameter in this method instead");
242 err.help("try using a local type parameter instead");
247 ResolutionError::NameAlreadyUsedInTypeParameterList(name, first_use_span) => {
248 let mut err = struct_span_err!(resolver.session,
251 "the name `{}` is already used for a type parameter \
252 in this type parameter list",
254 err.span_label(span, "already used");
255 err.span_label(first_use_span.clone(), format!("first use of `{}`", name));
258 ResolutionError::MethodNotMemberOfTrait(method, trait_) => {
259 let mut err = struct_span_err!(resolver.session,
262 "method `{}` is not a member of trait `{}`",
265 err.span_label(span, format!("not a member of trait `{}`", trait_));
268 ResolutionError::TypeNotMemberOfTrait(type_, trait_) => {
269 let mut err = struct_span_err!(resolver.session,
272 "type `{}` is not a member of trait `{}`",
275 err.span_label(span, format!("not a member of trait `{}`", trait_));
278 ResolutionError::ConstNotMemberOfTrait(const_, trait_) => {
279 let mut err = struct_span_err!(resolver.session,
282 "const `{}` is not a member of trait `{}`",
285 err.span_label(span, format!("not a member of trait `{}`", trait_));
288 ResolutionError::VariableNotBoundInPattern(binding_error) => {
289 let target_sp = binding_error.target.iter().cloned().collect::<Vec<_>>();
290 let msp = MultiSpan::from_spans(target_sp.clone());
291 let msg = format!("variable `{}` is not bound in all patterns", binding_error.name);
292 let mut err = resolver.session.struct_span_err_with_code(
295 DiagnosticId::Error("E0408".into()),
297 for sp in target_sp {
298 err.span_label(sp, format!("pattern doesn't bind `{}`", binding_error.name));
300 let origin_sp = binding_error.origin.iter().cloned();
301 for sp in origin_sp {
302 err.span_label(sp, "variable not in all patterns");
306 ResolutionError::VariableBoundWithDifferentMode(variable_name,
307 first_binding_span) => {
308 let mut err = struct_span_err!(resolver.session,
311 "variable `{}` is bound in inconsistent \
312 ways within the same match arm",
314 err.span_label(span, "bound in different ways");
315 err.span_label(first_binding_span, "first binding");
318 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(identifier) => {
319 let mut err = struct_span_err!(resolver.session,
322 "identifier `{}` is bound more than once in this parameter list",
324 err.span_label(span, "used as parameter more than once");
327 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(identifier) => {
328 let mut err = struct_span_err!(resolver.session,
331 "identifier `{}` is bound more than once in the same pattern",
333 err.span_label(span, "used in a pattern more than once");
336 ResolutionError::UndeclaredLabel(name, lev_candidate) => {
337 let mut err = struct_span_err!(resolver.session,
340 "use of undeclared label `{}`",
342 if let Some(lev_candidate) = lev_candidate {
343 err.span_label(span, format!("did you mean `{}`?", lev_candidate));
345 err.span_label(span, format!("undeclared label `{}`", name));
349 ResolutionError::SelfImportsOnlyAllowedWithin => {
350 struct_span_err!(resolver.session,
354 "`self` imports are only allowed within a { } list")
356 ResolutionError::SelfImportCanOnlyAppearOnceInTheList => {
357 let mut err = struct_span_err!(resolver.session, span, E0430,
358 "`self` import can only appear once in an import list");
359 err.span_label(span, "can only appear once in an import list");
362 ResolutionError::SelfImportOnlyInImportListWithNonEmptyPrefix => {
363 let mut err = struct_span_err!(resolver.session, span, E0431,
364 "`self` import can only appear in an import list with \
365 a non-empty prefix");
366 err.span_label(span, "can only appear in an import list with a non-empty prefix");
369 ResolutionError::FailedToResolve(msg) => {
370 let mut err = struct_span_err!(resolver.session, span, E0433,
371 "failed to resolve. {}", msg);
372 err.span_label(span, msg);
375 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem => {
376 let mut err = struct_span_err!(resolver.session,
380 "can't capture dynamic environment in a fn item");
381 err.help("use the `|| { ... }` closure form instead");
384 ResolutionError::AttemptToUseNonConstantValueInConstant => {
385 let mut err = struct_span_err!(resolver.session, span, E0435,
386 "attempt to use a non-constant value in a constant");
387 err.span_label(span, "non-constant value");
390 ResolutionError::BindingShadowsSomethingUnacceptable(what_binding, name, binding) => {
391 let shadows_what = PathResolution::new(binding.def()).kind_name();
392 let mut err = struct_span_err!(resolver.session,
395 "{}s cannot shadow {}s", what_binding, shadows_what);
396 err.span_label(span, format!("cannot be named the same as a {}", shadows_what));
397 let participle = if binding.is_import() { "imported" } else { "defined" };
398 let msg = format!("a {} `{}` is {} here", shadows_what, name, participle);
399 err.span_label(binding.span, msg);
402 ResolutionError::ForwardDeclaredTyParam => {
403 let mut err = struct_span_err!(resolver.session, span, E0128,
404 "type parameters with a default cannot use \
405 forward declared identifiers");
407 span, "defaulted type parameters cannot be forward declared".to_string());
413 /// Adjust the impl span so that just the `impl` keyword is taken by removing
414 /// everything after `<` (`"impl<T> Iterator for A<T> {}" -> "impl"`) and
415 /// everything after the first whitespace (`"impl Iterator for A" -> "impl"`)
417 /// Attention: The method used is very fragile since it essentially duplicates the work of the
418 /// parser. If you need to use this function or something similar, please consider updating the
419 /// source_map functions and this function to something more robust.
420 fn reduce_impl_span_to_impl_keyword(cm: &SourceMap, impl_span: Span) -> Span {
421 let impl_span = cm.span_until_char(impl_span, '<');
422 let impl_span = cm.span_until_whitespace(impl_span);
426 #[derive(Copy, Clone, Debug)]
429 binding_mode: BindingMode,
432 /// Map from the name in a pattern to its binding mode.
433 type BindingMap = FxHashMap<Ident, BindingInfo>;
435 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
446 fn descr(self) -> &'static str {
448 PatternSource::Match => "match binding",
449 PatternSource::IfLet => "if let binding",
450 PatternSource::WhileLet => "while let binding",
451 PatternSource::Let => "let binding",
452 PatternSource::For => "for binding",
453 PatternSource::FnParam => "function parameter",
458 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
459 enum AliasPossibility {
464 #[derive(Copy, Clone, Debug)]
465 enum PathSource<'a> {
466 // Type paths `Path`.
468 // Trait paths in bounds or impls.
469 Trait(AliasPossibility),
470 // Expression paths `path`, with optional parent context.
471 Expr(Option<&'a Expr>),
472 // Paths in path patterns `Path`.
474 // Paths in struct expressions and patterns `Path { .. }`.
476 // Paths in tuple struct patterns `Path(..)`.
478 // `m::A::B` in `<T as m::A>::B::C`.
479 TraitItem(Namespace),
480 // Path in `pub(path)`
482 // Path in `use a::b::{...};`
486 impl<'a> PathSource<'a> {
487 fn namespace(self) -> Namespace {
489 PathSource::Type | PathSource::Trait(_) | PathSource::Struct |
490 PathSource::Visibility | PathSource::ImportPrefix => TypeNS,
491 PathSource::Expr(..) | PathSource::Pat | PathSource::TupleStruct => ValueNS,
492 PathSource::TraitItem(ns) => ns,
496 fn global_by_default(self) -> bool {
498 PathSource::Visibility | PathSource::ImportPrefix => true,
499 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
500 PathSource::Struct | PathSource::TupleStruct |
501 PathSource::Trait(_) | PathSource::TraitItem(..) => false,
505 fn defer_to_typeck(self) -> bool {
507 PathSource::Type | PathSource::Expr(..) | PathSource::Pat |
508 PathSource::Struct | PathSource::TupleStruct => true,
509 PathSource::Trait(_) | PathSource::TraitItem(..) |
510 PathSource::Visibility | PathSource::ImportPrefix => false,
514 fn descr_expected(self) -> &'static str {
516 PathSource::Type => "type",
517 PathSource::Trait(_) => "trait",
518 PathSource::Pat => "unit struct/variant or constant",
519 PathSource::Struct => "struct, variant or union type",
520 PathSource::TupleStruct => "tuple struct/variant",
521 PathSource::Visibility => "module",
522 PathSource::ImportPrefix => "module or enum",
523 PathSource::TraitItem(ns) => match ns {
524 TypeNS => "associated type",
525 ValueNS => "method or associated constant",
526 MacroNS => bug!("associated macro"),
528 PathSource::Expr(parent) => match parent.map(|p| &p.node) {
529 // "function" here means "anything callable" rather than `Def::Fn`,
530 // this is not precise but usually more helpful than just "value".
531 Some(&ExprKind::Call(..)) => "function",
537 fn is_expected(self, def: Def) -> bool {
539 PathSource::Type => match def {
540 Def::Struct(..) | Def::Union(..) | Def::Enum(..) |
541 Def::Trait(..) | Def::TyAlias(..) | Def::AssociatedTy(..) |
542 Def::PrimTy(..) | Def::TyParam(..) | Def::SelfTy(..) |
543 Def::Existential(..) |
544 Def::ForeignTy(..) => true,
547 PathSource::Trait(AliasPossibility::No) => match def {
548 Def::Trait(..) => true,
551 PathSource::Trait(AliasPossibility::Maybe) => match def {
552 Def::Trait(..) => true,
553 Def::TraitAlias(..) => true,
556 PathSource::Expr(..) => match def {
557 Def::StructCtor(_, CtorKind::Const) | Def::StructCtor(_, CtorKind::Fn) |
558 Def::VariantCtor(_, CtorKind::Const) | Def::VariantCtor(_, CtorKind::Fn) |
559 Def::Const(..) | Def::Static(..) | Def::Local(..) | Def::Upvar(..) |
560 Def::Fn(..) | Def::Method(..) | Def::AssociatedConst(..) |
561 Def::SelfCtor(..) => true,
564 PathSource::Pat => match def {
565 Def::StructCtor(_, CtorKind::Const) |
566 Def::VariantCtor(_, CtorKind::Const) |
567 Def::Const(..) | Def::AssociatedConst(..) |
568 Def::SelfCtor(..) => true,
571 PathSource::TupleStruct => match def {
572 Def::StructCtor(_, CtorKind::Fn) |
573 Def::VariantCtor(_, CtorKind::Fn) |
574 Def::SelfCtor(..) => true,
577 PathSource::Struct => match def {
578 Def::Struct(..) | Def::Union(..) | Def::Variant(..) |
579 Def::TyAlias(..) | Def::AssociatedTy(..) | Def::SelfTy(..) => true,
582 PathSource::TraitItem(ns) => match def {
583 Def::AssociatedConst(..) | Def::Method(..) if ns == ValueNS => true,
584 Def::AssociatedTy(..) if ns == TypeNS => true,
587 PathSource::ImportPrefix => match def {
588 Def::Mod(..) | Def::Enum(..) => true,
591 PathSource::Visibility => match def {
592 Def::Mod(..) => true,
598 fn error_code(self, has_unexpected_resolution: bool) -> &'static str {
599 __diagnostic_used!(E0404);
600 __diagnostic_used!(E0405);
601 __diagnostic_used!(E0412);
602 __diagnostic_used!(E0422);
603 __diagnostic_used!(E0423);
604 __diagnostic_used!(E0425);
605 __diagnostic_used!(E0531);
606 __diagnostic_used!(E0532);
607 __diagnostic_used!(E0573);
608 __diagnostic_used!(E0574);
609 __diagnostic_used!(E0575);
610 __diagnostic_used!(E0576);
611 __diagnostic_used!(E0577);
612 __diagnostic_used!(E0578);
613 match (self, has_unexpected_resolution) {
614 (PathSource::Trait(_), true) => "E0404",
615 (PathSource::Trait(_), false) => "E0405",
616 (PathSource::Type, true) => "E0573",
617 (PathSource::Type, false) => "E0412",
618 (PathSource::Struct, true) => "E0574",
619 (PathSource::Struct, false) => "E0422",
620 (PathSource::Expr(..), true) => "E0423",
621 (PathSource::Expr(..), false) => "E0425",
622 (PathSource::Pat, true) | (PathSource::TupleStruct, true) => "E0532",
623 (PathSource::Pat, false) | (PathSource::TupleStruct, false) => "E0531",
624 (PathSource::TraitItem(..), true) => "E0575",
625 (PathSource::TraitItem(..), false) => "E0576",
626 (PathSource::Visibility, true) | (PathSource::ImportPrefix, true) => "E0577",
627 (PathSource::Visibility, false) | (PathSource::ImportPrefix, false) => "E0578",
632 struct UsePlacementFinder {
633 target_module: NodeId,
638 impl UsePlacementFinder {
639 fn check(krate: &Crate, target_module: NodeId) -> (Option<Span>, bool) {
640 let mut finder = UsePlacementFinder {
645 visit::walk_crate(&mut finder, krate);
646 (finder.span, finder.found_use)
650 impl<'tcx> Visitor<'tcx> for UsePlacementFinder {
653 module: &'tcx ast::Mod,
655 _: &[ast::Attribute],
658 if self.span.is_some() {
661 if node_id != self.target_module {
662 visit::walk_mod(self, module);
665 // find a use statement
666 for item in &module.items {
668 ItemKind::Use(..) => {
669 // don't suggest placing a use before the prelude
670 // import or other generated ones
671 if item.span.ctxt().outer().expn_info().is_none() {
672 self.span = Some(item.span.shrink_to_lo());
673 self.found_use = true;
677 // don't place use before extern crate
678 ItemKind::ExternCrate(_) => {}
679 // but place them before the first other item
680 _ => if self.span.map_or(true, |span| item.span < span ) {
681 if item.span.ctxt().outer().expn_info().is_none() {
682 // don't insert between attributes and an item
683 if item.attrs.is_empty() {
684 self.span = Some(item.span.shrink_to_lo());
686 // find the first attribute on the item
687 for attr in &item.attrs {
688 if self.span.map_or(true, |span| attr.span < span) {
689 self.span = Some(attr.span.shrink_to_lo());
700 /// This thing walks the whole crate in DFS manner, visiting each item, resolving names as it goes.
701 impl<'a, 'tcx, 'cl> Visitor<'tcx> for Resolver<'a, 'cl> {
702 fn visit_item(&mut self, item: &'tcx Item) {
703 self.resolve_item(item);
705 fn visit_arm(&mut self, arm: &'tcx Arm) {
706 self.resolve_arm(arm);
708 fn visit_block(&mut self, block: &'tcx Block) {
709 self.resolve_block(block);
711 fn visit_anon_const(&mut self, constant: &'tcx ast::AnonConst) {
712 self.with_constant_rib(|this| {
713 visit::walk_anon_const(this, constant);
716 fn visit_expr(&mut self, expr: &'tcx Expr) {
717 self.resolve_expr(expr, None);
719 fn visit_local(&mut self, local: &'tcx Local) {
720 self.resolve_local(local);
722 fn visit_ty(&mut self, ty: &'tcx Ty) {
724 TyKind::Path(ref qself, ref path) => {
725 self.smart_resolve_path(ty.id, qself.as_ref(), path, PathSource::Type);
727 TyKind::ImplicitSelf => {
728 let self_ty = keywords::SelfType.ident();
729 let def = self.resolve_ident_in_lexical_scope(self_ty, TypeNS, Some(ty.id), ty.span)
730 .map_or(Def::Err, |d| d.def());
731 self.record_def(ty.id, PathResolution::new(def));
735 visit::walk_ty(self, ty);
737 fn visit_poly_trait_ref(&mut self,
738 tref: &'tcx ast::PolyTraitRef,
739 m: &'tcx ast::TraitBoundModifier) {
740 self.smart_resolve_path(tref.trait_ref.ref_id, None,
741 &tref.trait_ref.path, PathSource::Trait(AliasPossibility::Maybe));
742 visit::walk_poly_trait_ref(self, tref, m);
744 fn visit_foreign_item(&mut self, foreign_item: &'tcx ForeignItem) {
745 let type_parameters = match foreign_item.node {
746 ForeignItemKind::Fn(_, ref generics) => {
747 HasTypeParameters(generics, ItemRibKind)
749 ForeignItemKind::Static(..) => NoTypeParameters,
750 ForeignItemKind::Ty => NoTypeParameters,
751 ForeignItemKind::Macro(..) => NoTypeParameters,
753 self.with_type_parameter_rib(type_parameters, |this| {
754 visit::walk_foreign_item(this, foreign_item);
757 fn visit_fn(&mut self,
758 function_kind: FnKind<'tcx>,
759 declaration: &'tcx FnDecl,
763 let (rib_kind, asyncness) = match function_kind {
764 FnKind::ItemFn(_, ref header, ..) =>
765 (ItemRibKind, header.asyncness),
766 FnKind::Method(_, ref sig, _, _) =>
767 (TraitOrImplItemRibKind, sig.header.asyncness),
768 FnKind::Closure(_) =>
769 // Async closures aren't resolved through `visit_fn`-- they're
770 // processed separately
771 (ClosureRibKind(node_id), IsAsync::NotAsync),
774 // Create a value rib for the function.
775 self.ribs[ValueNS].push(Rib::new(rib_kind));
777 // Create a label rib for the function.
778 self.label_ribs.push(Rib::new(rib_kind));
780 // Add each argument to the rib.
781 let mut bindings_list = FxHashMap();
782 for argument in &declaration.inputs {
783 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
785 self.visit_ty(&argument.ty);
787 debug!("(resolving function) recorded argument");
789 visit::walk_fn_ret_ty(self, &declaration.output);
791 // Resolve the function body, potentially inside the body of an async closure
792 if let IsAsync::Async { closure_id, .. } = asyncness {
793 let rib_kind = ClosureRibKind(closure_id);
794 self.ribs[ValueNS].push(Rib::new(rib_kind));
795 self.label_ribs.push(Rib::new(rib_kind));
798 match function_kind {
799 FnKind::ItemFn(.., body) |
800 FnKind::Method(.., body) => {
801 self.visit_block(body);
803 FnKind::Closure(body) => {
804 self.visit_expr(body);
808 // Leave the body of the async closure
809 if asyncness.is_async() {
810 self.label_ribs.pop();
811 self.ribs[ValueNS].pop();
814 debug!("(resolving function) leaving function");
816 self.label_ribs.pop();
817 self.ribs[ValueNS].pop();
819 fn visit_generics(&mut self, generics: &'tcx Generics) {
820 // For type parameter defaults, we have to ban access
821 // to following type parameters, as the Substs can only
822 // provide previous type parameters as they're built. We
823 // put all the parameters on the ban list and then remove
824 // them one by one as they are processed and become available.
825 let mut default_ban_rib = Rib::new(ForwardTyParamBanRibKind);
826 let mut found_default = false;
827 default_ban_rib.bindings.extend(generics.params.iter()
828 .filter_map(|param| match param.kind {
829 GenericParamKind::Lifetime { .. } => None,
830 GenericParamKind::Type { ref default, .. } => {
831 found_default |= default.is_some();
833 Some((Ident::with_empty_ctxt(param.ident.name), Def::Err))
840 for param in &generics.params {
842 GenericParamKind::Lifetime { .. } => self.visit_generic_param(param),
843 GenericParamKind::Type { ref default, .. } => {
844 for bound in ¶m.bounds {
845 self.visit_param_bound(bound);
848 if let Some(ref ty) = default {
849 self.ribs[TypeNS].push(default_ban_rib);
851 default_ban_rib = self.ribs[TypeNS].pop().unwrap();
854 // Allow all following defaults to refer to this type parameter.
855 default_ban_rib.bindings.remove(&Ident::with_empty_ctxt(param.ident.name));
859 for p in &generics.where_clause.predicates {
860 self.visit_where_predicate(p);
865 #[derive(Copy, Clone)]
866 enum TypeParameters<'a, 'b> {
868 HasTypeParameters(// Type parameters.
871 // The kind of the rib used for type parameters.
875 /// The rib kind controls the translation of local
876 /// definitions (`Def::Local`) to upvars (`Def::Upvar`).
877 #[derive(Copy, Clone, Debug)]
879 /// No translation needs to be applied.
882 /// We passed through a closure scope at the given node ID.
883 /// Translate upvars as appropriate.
884 ClosureRibKind(NodeId /* func id */),
886 /// We passed through an impl or trait and are now in one of its
887 /// methods or associated types. Allow references to ty params that impl or trait
888 /// binds. Disallow any other upvars (including other ty params that are
890 TraitOrImplItemRibKind,
892 /// We passed through an item scope. Disallow upvars.
895 /// We're in a constant item. Can't refer to dynamic stuff.
898 /// We passed through a module.
899 ModuleRibKind(Module<'a>),
901 /// We passed through a `macro_rules!` statement
902 MacroDefinition(DefId),
904 /// All bindings in this rib are type parameters that can't be used
905 /// from the default of a type parameter because they're not declared
906 /// before said type parameter. Also see the `visit_generics` override.
907 ForwardTyParamBanRibKind,
912 /// A rib represents a scope names can live in. Note that these appear in many places, not just
913 /// around braces. At any place where the list of accessible names (of the given namespace)
914 /// changes or a new restrictions on the name accessibility are introduced, a new rib is put onto a
915 /// stack. This may be, for example, a `let` statement (because it introduces variables), a macro,
918 /// Different [rib kinds](enum.RibKind) are transparent for different names.
920 /// The resolution keeps a separate stack of ribs as it traverses the AST for each namespace. When
921 /// resolving, the name is looked up from inside out.
924 bindings: FxHashMap<Ident, Def>,
929 fn new(kind: RibKind<'a>) -> Rib<'a> {
931 bindings: FxHashMap(),
937 /// An intermediate resolution result.
939 /// This refers to the thing referred by a name. The difference between `Def` and `Item` is that
940 /// items are visible in their whole block, while defs only from the place they are defined
942 enum LexicalScopeBinding<'a> {
943 Item(&'a NameBinding<'a>),
947 impl<'a> LexicalScopeBinding<'a> {
948 fn item(self) -> Option<&'a NameBinding<'a>> {
950 LexicalScopeBinding::Item(binding) => Some(binding),
955 fn def(self) -> Def {
957 LexicalScopeBinding::Item(binding) => binding.def(),
958 LexicalScopeBinding::Def(def) => def,
963 #[derive(Copy, Clone, Debug)]
964 pub enum ModuleOrUniformRoot<'a> {
968 /// The `{{root}}` (`CrateRoot` aka "global") / `extern` initial segment
969 /// in which external crates resolve, and also `crate` (only in `{{root}}`,
970 /// but *not* `extern`), in the Rust 2018 edition.
974 #[derive(Clone, Debug)]
975 enum PathResult<'a> {
976 Module(ModuleOrUniformRoot<'a>),
977 NonModule(PathResolution),
979 Failed(Span, String, bool /* is the error from the last segment? */),
983 /// An anonymous module, eg. just a block.
988 /// { // This is an anonymous module
989 /// f(); // This resolves to (2) as we are inside the block.
992 /// f(); // Resolves to (1)
996 /// Any module with a name.
1000 /// * A normal module ‒ either `mod from_file;` or `mod from_block { }`.
1001 /// * A trait or an enum (it implicitly contains associated types, methods and variant
1006 /// One node in the tree of modules.
1007 pub struct ModuleData<'a> {
1008 parent: Option<Module<'a>>,
1011 // The def id of the closest normal module (`mod`) ancestor (including this module).
1012 normal_ancestor_id: DefId,
1014 resolutions: RefCell<FxHashMap<(Ident, Namespace), &'a RefCell<NameResolution<'a>>>>,
1015 legacy_macro_resolutions: RefCell<Vec<(Ident, MacroKind, ParentScope<'a>, Option<Def>)>>,
1016 macro_resolutions: RefCell<Vec<(Box<[Ident]>, Span)>>,
1017 builtin_attrs: RefCell<Vec<(Ident, ParentScope<'a>)>>,
1019 // Macro invocations that can expand into items in this module.
1020 unresolved_invocations: RefCell<FxHashSet<Mark>>,
1022 no_implicit_prelude: bool,
1024 glob_importers: RefCell<Vec<&'a ImportDirective<'a>>>,
1025 globs: RefCell<Vec<&'a ImportDirective<'a>>>,
1027 // Used to memoize the traits in this module for faster searches through all traits in scope.
1028 traits: RefCell<Option<Box<[(Ident, &'a NameBinding<'a>)]>>>,
1030 // Whether this module is populated. If not populated, any attempt to
1031 // access the children must be preceded with a
1032 // `populate_module_if_necessary` call.
1033 populated: Cell<bool>,
1035 /// Span of the module itself. Used for error reporting.
1041 type Module<'a> = &'a ModuleData<'a>;
1043 impl<'a> ModuleData<'a> {
1044 fn new(parent: Option<Module<'a>>,
1046 normal_ancestor_id: DefId,
1048 span: Span) -> Self {
1053 resolutions: RefCell::new(FxHashMap()),
1054 legacy_macro_resolutions: RefCell::new(Vec::new()),
1055 macro_resolutions: RefCell::new(Vec::new()),
1056 builtin_attrs: RefCell::new(Vec::new()),
1057 unresolved_invocations: RefCell::new(FxHashSet()),
1058 no_implicit_prelude: false,
1059 glob_importers: RefCell::new(Vec::new()),
1060 globs: RefCell::new(Vec::new()),
1061 traits: RefCell::new(None),
1062 populated: Cell::new(normal_ancestor_id.is_local()),
1068 fn for_each_child<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1069 for (&(ident, ns), name_resolution) in self.resolutions.borrow().iter() {
1070 name_resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1074 fn for_each_child_stable<F: FnMut(Ident, Namespace, &'a NameBinding<'a>)>(&self, mut f: F) {
1075 let resolutions = self.resolutions.borrow();
1076 let mut resolutions = resolutions.iter().collect::<Vec<_>>();
1077 resolutions.sort_by_cached_key(|&(&(ident, ns), _)| (ident.as_str(), ns));
1078 for &(&(ident, ns), &resolution) in resolutions.iter() {
1079 resolution.borrow().binding.map(|binding| f(ident, ns, binding));
1083 fn def(&self) -> Option<Def> {
1085 ModuleKind::Def(def, _) => Some(def),
1090 fn def_id(&self) -> Option<DefId> {
1091 self.def().as_ref().map(Def::def_id)
1094 // `self` resolves to the first module ancestor that `is_normal`.
1095 fn is_normal(&self) -> bool {
1097 ModuleKind::Def(Def::Mod(_), _) => true,
1102 fn is_trait(&self) -> bool {
1104 ModuleKind::Def(Def::Trait(_), _) => true,
1109 fn is_local(&self) -> bool {
1110 self.normal_ancestor_id.is_local()
1113 fn nearest_item_scope(&'a self) -> Module<'a> {
1114 if self.is_trait() { self.parent.unwrap() } else { self }
1118 impl<'a> fmt::Debug for ModuleData<'a> {
1119 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1120 write!(f, "{:?}", self.def())
1124 /// Records a possibly-private value, type, or module definition.
1125 #[derive(Clone, Debug)]
1126 pub struct NameBinding<'a> {
1127 kind: NameBindingKind<'a>,
1130 vis: ty::Visibility,
1133 pub trait ToNameBinding<'a> {
1134 fn to_name_binding(self, arenas: &'a ResolverArenas<'a>) -> &'a NameBinding<'a>;
1137 impl<'a> ToNameBinding<'a> for &'a NameBinding<'a> {
1138 fn to_name_binding(self, _: &'a ResolverArenas<'a>) -> &'a NameBinding<'a> {
1143 #[derive(Clone, Debug)]
1144 enum NameBindingKind<'a> {
1145 Def(Def, /* is_macro_export */ bool),
1148 binding: &'a NameBinding<'a>,
1149 directive: &'a ImportDirective<'a>,
1153 b1: &'a NameBinding<'a>,
1154 b2: &'a NameBinding<'a>,
1158 struct PrivacyError<'a>(Span, Name, &'a NameBinding<'a>);
1160 struct UseError<'a> {
1161 err: DiagnosticBuilder<'a>,
1162 /// Attach `use` statements for these candidates
1163 candidates: Vec<ImportSuggestion>,
1164 /// The node id of the module to place the use statements in
1166 /// Whether the diagnostic should state that it's "better"
1170 struct AmbiguityError<'a> {
1172 b1: &'a NameBinding<'a>,
1173 b2: &'a NameBinding<'a>,
1176 impl<'a> NameBinding<'a> {
1177 fn module(&self) -> Option<Module<'a>> {
1179 NameBindingKind::Module(module) => Some(module),
1180 NameBindingKind::Import { binding, .. } => binding.module(),
1185 fn def(&self) -> Def {
1187 NameBindingKind::Def(def, _) => def,
1188 NameBindingKind::Module(module) => module.def().unwrap(),
1189 NameBindingKind::Import { binding, .. } => binding.def(),
1190 NameBindingKind::Ambiguity { .. } => Def::Err,
1194 fn def_ignoring_ambiguity(&self) -> Def {
1196 NameBindingKind::Import { binding, .. } => binding.def_ignoring_ambiguity(),
1197 NameBindingKind::Ambiguity { b1, .. } => b1.def_ignoring_ambiguity(),
1202 fn get_macro<'b: 'a>(&self, resolver: &mut Resolver<'a, 'b>) -> Lrc<SyntaxExtension> {
1203 resolver.get_macro(self.def_ignoring_ambiguity())
1206 // We sometimes need to treat variants as `pub` for backwards compatibility
1207 fn pseudo_vis(&self) -> ty::Visibility {
1208 if self.is_variant() && self.def().def_id().is_local() {
1209 ty::Visibility::Public
1215 fn is_variant(&self) -> bool {
1217 NameBindingKind::Def(Def::Variant(..), _) |
1218 NameBindingKind::Def(Def::VariantCtor(..), _) => true,
1223 fn is_extern_crate(&self) -> bool {
1225 NameBindingKind::Import {
1226 directive: &ImportDirective {
1227 subclass: ImportDirectiveSubclass::ExternCrate(_), ..
1234 fn is_import(&self) -> bool {
1236 NameBindingKind::Import { .. } => true,
1241 fn is_renamed_extern_crate(&self) -> bool {
1242 if let NameBindingKind::Import { directive, ..} = self.kind {
1243 if let ImportDirectiveSubclass::ExternCrate(Some(_)) = directive.subclass {
1250 fn is_glob_import(&self) -> bool {
1252 NameBindingKind::Import { directive, .. } => directive.is_glob(),
1253 NameBindingKind::Ambiguity { b1, .. } => b1.is_glob_import(),
1258 fn is_importable(&self) -> bool {
1260 Def::AssociatedConst(..) | Def::Method(..) | Def::AssociatedTy(..) => false,
1265 fn is_macro_def(&self) -> bool {
1267 NameBindingKind::Def(Def::Macro(..), _) => true,
1272 fn macro_kind(&self) -> Option<MacroKind> {
1273 match self.def_ignoring_ambiguity() {
1274 Def::Macro(_, kind) => Some(kind),
1275 Def::NonMacroAttr(..) => Some(MacroKind::Attr),
1280 fn descr(&self) -> &'static str {
1281 if self.is_extern_crate() { "extern crate" } else { self.def().kind_name() }
1284 // Suppose that we resolved macro invocation with `invoc_parent_expansion` to binding `binding`
1285 // at some expansion round `max(invoc, binding)` when they both emerged from macros.
1286 // Then this function returns `true` if `self` may emerge from a macro *after* that
1287 // in some later round and screw up our previously found resolution.
1288 // See more detailed explanation in
1289 // https://github.com/rust-lang/rust/pull/53778#issuecomment-419224049
1290 fn may_appear_after(&self, invoc_parent_expansion: Mark, binding: &NameBinding) -> bool {
1291 // self > max(invoc, binding) => !(self <= invoc || self <= binding)
1292 // Expansions are partially ordered, so "may appear after" is an inversion of
1293 // "certainly appears before or simultaneously" and includes unordered cases.
1294 let self_parent_expansion = self.expansion;
1295 let other_parent_expansion = binding.expansion;
1296 let certainly_before_other_or_simultaneously =
1297 other_parent_expansion.is_descendant_of(self_parent_expansion);
1298 let certainly_before_invoc_or_simultaneously =
1299 invoc_parent_expansion.is_descendant_of(self_parent_expansion);
1300 !(certainly_before_other_or_simultaneously || certainly_before_invoc_or_simultaneously)
1304 /// Interns the names of the primitive types.
1306 /// All other types are defined somewhere and possibly imported, but the primitive ones need
1307 /// special handling, since they have no place of origin.
1308 struct PrimitiveTypeTable {
1309 primitive_types: FxHashMap<Name, PrimTy>,
1312 impl PrimitiveTypeTable {
1313 fn new() -> PrimitiveTypeTable {
1314 let mut table = PrimitiveTypeTable { primitive_types: FxHashMap() };
1316 table.intern("bool", Bool);
1317 table.intern("char", Char);
1318 table.intern("f32", Float(FloatTy::F32));
1319 table.intern("f64", Float(FloatTy::F64));
1320 table.intern("isize", Int(IntTy::Isize));
1321 table.intern("i8", Int(IntTy::I8));
1322 table.intern("i16", Int(IntTy::I16));
1323 table.intern("i32", Int(IntTy::I32));
1324 table.intern("i64", Int(IntTy::I64));
1325 table.intern("i128", Int(IntTy::I128));
1326 table.intern("str", Str);
1327 table.intern("usize", Uint(UintTy::Usize));
1328 table.intern("u8", Uint(UintTy::U8));
1329 table.intern("u16", Uint(UintTy::U16));
1330 table.intern("u32", Uint(UintTy::U32));
1331 table.intern("u64", Uint(UintTy::U64));
1332 table.intern("u128", Uint(UintTy::U128));
1336 fn intern(&mut self, string: &str, primitive_type: PrimTy) {
1337 self.primitive_types.insert(Symbol::intern(string), primitive_type);
1341 /// The main resolver class.
1343 /// This is the visitor that walks the whole crate.
1344 pub struct Resolver<'a, 'b: 'a> {
1345 session: &'a Session,
1348 pub definitions: Definitions,
1350 graph_root: Module<'a>,
1352 prelude: Option<Module<'a>>,
1353 extern_prelude: FxHashSet<Name>,
1355 /// n.b. This is used only for better diagnostics, not name resolution itself.
1356 has_self: FxHashSet<DefId>,
1358 /// Names of fields of an item `DefId` accessible with dot syntax.
1359 /// Used for hints during error reporting.
1360 field_names: FxHashMap<DefId, Vec<Name>>,
1362 /// All imports known to succeed or fail.
1363 determined_imports: Vec<&'a ImportDirective<'a>>,
1365 /// All non-determined imports.
1366 indeterminate_imports: Vec<&'a ImportDirective<'a>>,
1368 /// The module that represents the current item scope.
1369 current_module: Module<'a>,
1371 /// The current set of local scopes for types and values.
1372 /// FIXME #4948: Reuse ribs to avoid allocation.
1373 ribs: PerNS<Vec<Rib<'a>>>,
1375 /// The current set of local scopes, for labels.
1376 label_ribs: Vec<Rib<'a>>,
1378 /// The trait that the current context can refer to.
1379 current_trait_ref: Option<(Module<'a>, TraitRef)>,
1381 /// The current self type if inside an impl (used for better errors).
1382 current_self_type: Option<Ty>,
1384 /// The idents for the primitive types.
1385 primitive_type_table: PrimitiveTypeTable,
1388 import_map: ImportMap,
1389 pub freevars: FreevarMap,
1390 freevars_seen: NodeMap<NodeMap<usize>>,
1391 pub export_map: ExportMap,
1392 pub trait_map: TraitMap,
1394 /// A map from nodes to anonymous modules.
1395 /// Anonymous modules are pseudo-modules that are implicitly created around items
1396 /// contained within blocks.
1398 /// For example, if we have this:
1406 /// There will be an anonymous module created around `g` with the ID of the
1407 /// entry block for `f`.
1408 block_map: NodeMap<Module<'a>>,
1409 module_map: FxHashMap<DefId, Module<'a>>,
1410 extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
1412 pub make_glob_map: bool,
1413 /// Maps imports to the names of items actually imported (this actually maps
1414 /// all imports, but only glob imports are actually interesting).
1415 pub glob_map: GlobMap,
1417 used_imports: FxHashSet<(NodeId, Namespace)>,
1418 pub maybe_unused_trait_imports: NodeSet,
1419 pub maybe_unused_extern_crates: Vec<(NodeId, Span)>,
1421 /// A list of labels as of yet unused. Labels will be removed from this map when
1422 /// they are used (in a `break` or `continue` statement)
1423 pub unused_labels: FxHashMap<NodeId, Span>,
1425 /// privacy errors are delayed until the end in order to deduplicate them
1426 privacy_errors: Vec<PrivacyError<'a>>,
1427 /// ambiguity errors are delayed for deduplication
1428 ambiguity_errors: Vec<AmbiguityError<'a>>,
1429 /// `use` injections are delayed for better placement and deduplication
1430 use_injections: Vec<UseError<'a>>,
1431 /// crate-local macro expanded `macro_export` referred to by a module-relative path
1432 macro_expanded_macro_export_errors: BTreeSet<(Span, Span)>,
1434 arenas: &'a ResolverArenas<'a>,
1435 dummy_binding: &'a NameBinding<'a>,
1437 crate_loader: &'a mut CrateLoader<'b>,
1438 macro_names: FxHashSet<Ident>,
1439 builtin_macros: FxHashMap<Name, &'a NameBinding<'a>>,
1440 macro_use_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
1441 pub all_macros: FxHashMap<Name, Def>,
1442 macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
1443 macro_defs: FxHashMap<Mark, DefId>,
1444 local_macro_def_scopes: FxHashMap<NodeId, Module<'a>>,
1445 pub whitelisted_legacy_custom_derives: Vec<Name>,
1446 pub found_unresolved_macro: bool,
1448 /// List of crate local macros that we need to warn about as being unused.
1449 /// Right now this only includes macro_rules! macros, and macros 2.0.
1450 unused_macros: FxHashSet<DefId>,
1452 /// Maps the `Mark` of an expansion to its containing module or block.
1453 invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
1455 /// Avoid duplicated errors for "name already defined".
1456 name_already_seen: FxHashMap<Name, Span>,
1458 potentially_unused_imports: Vec<&'a ImportDirective<'a>>,
1460 /// This table maps struct IDs into struct constructor IDs,
1461 /// it's not used during normal resolution, only for better error reporting.
1462 struct_constructors: DefIdMap<(Def, ty::Visibility)>,
1464 /// Only used for better errors on `fn(): fn()`
1465 current_type_ascription: Vec<Span>,
1467 injected_crate: Option<Module<'a>>,
1470 /// Nothing really interesting here, it just provides memory for the rest of the crate.
1471 pub struct ResolverArenas<'a> {
1472 modules: arena::TypedArena<ModuleData<'a>>,
1473 local_modules: RefCell<Vec<Module<'a>>>,
1474 name_bindings: arena::TypedArena<NameBinding<'a>>,
1475 import_directives: arena::TypedArena<ImportDirective<'a>>,
1476 name_resolutions: arena::TypedArena<RefCell<NameResolution<'a>>>,
1477 invocation_data: arena::TypedArena<InvocationData<'a>>,
1478 legacy_bindings: arena::TypedArena<LegacyBinding<'a>>,
1481 impl<'a> ResolverArenas<'a> {
1482 fn alloc_module(&'a self, module: ModuleData<'a>) -> Module<'a> {
1483 let module = self.modules.alloc(module);
1484 if module.def_id().map(|def_id| def_id.is_local()).unwrap_or(true) {
1485 self.local_modules.borrow_mut().push(module);
1489 fn local_modules(&'a self) -> ::std::cell::Ref<'a, Vec<Module<'a>>> {
1490 self.local_modules.borrow()
1492 fn alloc_name_binding(&'a self, name_binding: NameBinding<'a>) -> &'a NameBinding<'a> {
1493 self.name_bindings.alloc(name_binding)
1495 fn alloc_import_directive(&'a self, import_directive: ImportDirective<'a>)
1496 -> &'a ImportDirective {
1497 self.import_directives.alloc(import_directive)
1499 fn alloc_name_resolution(&'a self) -> &'a RefCell<NameResolution<'a>> {
1500 self.name_resolutions.alloc(Default::default())
1502 fn alloc_invocation_data(&'a self, expansion_data: InvocationData<'a>)
1503 -> &'a InvocationData<'a> {
1504 self.invocation_data.alloc(expansion_data)
1506 fn alloc_legacy_binding(&'a self, binding: LegacyBinding<'a>) -> &'a LegacyBinding<'a> {
1507 self.legacy_bindings.alloc(binding)
1511 impl<'a, 'b: 'a, 'cl: 'b> ty::DefIdTree for &'a Resolver<'b, 'cl> {
1512 fn parent(self, id: DefId) -> Option<DefId> {
1514 LOCAL_CRATE => self.definitions.def_key(id.index).parent,
1515 _ => self.cstore.def_key(id).parent,
1516 }.map(|index| DefId { index, ..id })
1520 /// This interface is used through the AST→HIR step, to embed full paths into the HIR. After that
1521 /// the resolver is no longer needed as all the relevant information is inline.
1522 impl<'a, 'cl> hir::lowering::Resolver for Resolver<'a, 'cl> {
1523 fn resolve_hir_path(&mut self, path: &mut hir::Path, is_value: bool) {
1524 self.resolve_hir_path_cb(path, is_value,
1525 |resolver, span, error| resolve_error(resolver, span, error))
1528 fn resolve_str_path(
1531 crate_root: Option<&str>,
1532 components: &[&str],
1533 args: Option<P<hir::GenericArgs>>,
1536 let mut segments = iter::once(keywords::CrateRoot.ident())
1538 crate_root.into_iter()
1539 .chain(components.iter().cloned())
1540 .map(Ident::from_str)
1541 ).map(hir::PathSegment::from_ident).collect::<Vec<_>>();
1543 if let Some(args) = args {
1544 let ident = segments.last().unwrap().ident;
1545 *segments.last_mut().unwrap() = hir::PathSegment {
1552 let mut path = hir::Path {
1555 segments: segments.into(),
1558 self.resolve_hir_path(&mut path, is_value);
1562 fn get_resolution(&mut self, id: NodeId) -> Option<PathResolution> {
1563 self.def_map.get(&id).cloned()
1566 fn get_import(&mut self, id: NodeId) -> PerNS<Option<PathResolution>> {
1567 self.import_map.get(&id).cloned().unwrap_or_default()
1570 fn definitions(&mut self) -> &mut Definitions {
1571 &mut self.definitions
1575 impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
1576 /// Rustdoc uses this to resolve things in a recoverable way. ResolutionError<'a>
1577 /// isn't something that can be returned because it can't be made to live that long,
1578 /// and also it's a private type. Fortunately rustdoc doesn't need to know the error,
1579 /// just that an error occurred.
1580 pub fn resolve_str_path_error(&mut self, span: Span, path_str: &str, is_value: bool)
1581 -> Result<hir::Path, ()> {
1583 let mut errored = false;
1585 let mut path = if path_str.starts_with("::") {
1589 segments: iter::once(keywords::CrateRoot.ident()).chain({
1590 path_str.split("::").skip(1).map(Ident::from_str)
1591 }).map(hir::PathSegment::from_ident).collect(),
1597 segments: path_str.split("::").map(Ident::from_str)
1598 .map(hir::PathSegment::from_ident).collect(),
1601 self.resolve_hir_path_cb(&mut path, is_value, |_, _, _| errored = true);
1602 if errored || path.def == Def::Err {
1609 /// resolve_hir_path, but takes a callback in case there was an error
1610 fn resolve_hir_path_cb<F>(&mut self, path: &mut hir::Path, is_value: bool, error_callback: F)
1611 where F: for<'c, 'b> FnOnce(&'c mut Resolver, Span, ResolutionError<'b>)
1613 let namespace = if is_value { ValueNS } else { TypeNS };
1614 let hir::Path { ref segments, span, ref mut def } = *path;
1615 let path: Vec<_> = segments.iter().map(|seg| seg.ident).collect();
1616 // FIXME (Manishearth): Intra doc links won't get warned of epoch changes
1617 match self.resolve_path(None, &path, Some(namespace), true, span, CrateLint::No) {
1618 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
1619 *def = module.def().unwrap(),
1620 PathResult::NonModule(path_res) if path_res.unresolved_segments() == 0 =>
1621 *def = path_res.base_def(),
1622 PathResult::NonModule(..) => match self.resolve_path(
1630 PathResult::Failed(span, msg, _) => {
1631 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1635 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
1636 PathResult::Indeterminate => unreachable!(),
1637 PathResult::Failed(span, msg, _) => {
1638 error_callback(self, span, ResolutionError::FailedToResolve(&msg));
1644 impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
1645 pub fn new(session: &'a Session,
1649 make_glob_map: MakeGlobMap,
1650 crate_loader: &'a mut CrateLoader<'crateloader>,
1651 arenas: &'a ResolverArenas<'a>)
1652 -> Resolver<'a, 'crateloader> {
1653 let root_def_id = DefId::local(CRATE_DEF_INDEX);
1654 let root_module_kind = ModuleKind::Def(Def::Mod(root_def_id), keywords::Invalid.name());
1655 let graph_root = arenas.alloc_module(ModuleData {
1656 no_implicit_prelude: attr::contains_name(&krate.attrs, "no_implicit_prelude"),
1657 ..ModuleData::new(None, root_module_kind, root_def_id, Mark::root(), krate.span)
1659 let mut module_map = FxHashMap();
1660 module_map.insert(DefId::local(CRATE_DEF_INDEX), graph_root);
1662 let mut definitions = Definitions::new();
1663 DefCollector::new(&mut definitions, Mark::root())
1664 .collect_root(crate_name, session.local_crate_disambiguator());
1666 let mut extern_prelude: FxHashSet<Name> =
1667 session.opts.externs.iter().map(|kv| Symbol::intern(kv.0)).collect();
1669 // HACK(eddyb) this ignore the `no_{core,std}` attributes.
1670 // FIXME(eddyb) warn (elsewhere) if core/std is used with `no_{core,std}`.
1671 // if !attr::contains_name(&krate.attrs, "no_core") {
1672 // if !attr::contains_name(&krate.attrs, "no_std") {
1673 extern_prelude.insert(Symbol::intern("core"));
1674 extern_prelude.insert(Symbol::intern("std"));
1675 extern_prelude.insert(Symbol::intern("meta"));
1677 let mut invocations = FxHashMap();
1678 invocations.insert(Mark::root(),
1679 arenas.alloc_invocation_data(InvocationData::root(graph_root)));
1681 let mut macro_defs = FxHashMap();
1682 macro_defs.insert(Mark::root(), root_def_id);
1691 // The outermost module has def ID 0; this is not reflected in the
1697 has_self: FxHashSet(),
1698 field_names: FxHashMap(),
1700 determined_imports: Vec::new(),
1701 indeterminate_imports: Vec::new(),
1703 current_module: graph_root,
1705 value_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1706 type_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1707 macro_ns: vec![Rib::new(ModuleRibKind(graph_root))],
1709 label_ribs: Vec::new(),
1711 current_trait_ref: None,
1712 current_self_type: None,
1714 primitive_type_table: PrimitiveTypeTable::new(),
1717 import_map: NodeMap(),
1718 freevars: NodeMap(),
1719 freevars_seen: NodeMap(),
1720 export_map: FxHashMap(),
1721 trait_map: NodeMap(),
1723 block_map: NodeMap(),
1724 extern_module_map: FxHashMap(),
1726 make_glob_map: make_glob_map == MakeGlobMap::Yes,
1727 glob_map: NodeMap(),
1729 used_imports: FxHashSet(),
1730 maybe_unused_trait_imports: NodeSet(),
1731 maybe_unused_extern_crates: Vec::new(),
1733 unused_labels: FxHashMap(),
1735 privacy_errors: Vec::new(),
1736 ambiguity_errors: Vec::new(),
1737 use_injections: Vec::new(),
1738 macro_expanded_macro_export_errors: BTreeSet::new(),
1741 dummy_binding: arenas.alloc_name_binding(NameBinding {
1742 kind: NameBindingKind::Def(Def::Err, false),
1743 expansion: Mark::root(),
1745 vis: ty::Visibility::Public,
1749 macro_names: FxHashSet(),
1750 builtin_macros: FxHashMap(),
1751 macro_use_prelude: FxHashMap(),
1752 all_macros: FxHashMap(),
1753 macro_map: FxHashMap(),
1756 local_macro_def_scopes: FxHashMap(),
1757 name_already_seen: FxHashMap(),
1758 whitelisted_legacy_custom_derives: Vec::new(),
1759 potentially_unused_imports: Vec::new(),
1760 struct_constructors: DefIdMap(),
1761 found_unresolved_macro: false,
1762 unused_macros: FxHashSet(),
1763 current_type_ascription: Vec::new(),
1764 injected_crate: None,
1768 pub fn arenas() -> ResolverArenas<'a> {
1770 modules: arena::TypedArena::new(),
1771 local_modules: RefCell::new(Vec::new()),
1772 name_bindings: arena::TypedArena::new(),
1773 import_directives: arena::TypedArena::new(),
1774 name_resolutions: arena::TypedArena::new(),
1775 invocation_data: arena::TypedArena::new(),
1776 legacy_bindings: arena::TypedArena::new(),
1780 /// Runs the function on each namespace.
1781 fn per_ns<F: FnMut(&mut Self, Namespace)>(&mut self, mut f: F) {
1787 fn macro_def(&self, mut ctxt: SyntaxContext) -> DefId {
1789 match self.macro_defs.get(&ctxt.outer()) {
1790 Some(&def_id) => return def_id,
1791 None => ctxt.remove_mark(),
1796 /// Entry point to crate resolution.
1797 pub fn resolve_crate(&mut self, krate: &Crate) {
1798 ImportResolver { resolver: self }.finalize_imports();
1799 self.current_module = self.graph_root;
1800 self.finalize_current_module_macro_resolutions();
1802 visit::walk_crate(self, krate);
1804 check_unused::check_crate(self, krate);
1805 self.report_errors(krate);
1806 self.crate_loader.postprocess(krate);
1813 normal_ancestor_id: DefId,
1817 let module = ModuleData::new(Some(parent), kind, normal_ancestor_id, expansion, span);
1818 self.arenas.alloc_module(module)
1821 fn record_use(&mut self, ident: Ident, ns: Namespace, binding: &'a NameBinding<'a>)
1822 -> bool /* true if an error was reported */ {
1823 match binding.kind {
1824 NameBindingKind::Import { directive, binding, ref used }
1827 directive.used.set(true);
1828 self.used_imports.insert((directive.id, ns));
1829 self.add_to_glob_map(directive.id, ident);
1830 self.record_use(ident, ns, binding)
1832 NameBindingKind::Import { .. } => false,
1833 NameBindingKind::Ambiguity { b1, b2 } => {
1834 self.ambiguity_errors.push(AmbiguityError { ident, b1, b2 });
1841 fn add_to_glob_map(&mut self, id: NodeId, ident: Ident) {
1842 if self.make_glob_map {
1843 self.glob_map.entry(id).or_default().insert(ident.name);
1847 /// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
1848 /// More specifically, we proceed up the hierarchy of scopes and return the binding for
1849 /// `ident` in the first scope that defines it (or None if no scopes define it).
1851 /// A block's items are above its local variables in the scope hierarchy, regardless of where
1852 /// the items are defined in the block. For example,
1855 /// g(); // Since there are no local variables in scope yet, this resolves to the item.
1858 /// g(); // This resolves to the local variable `g` since it shadows the item.
1862 /// Invariant: This must only be called during main resolution, not during
1863 /// import resolution.
1864 fn resolve_ident_in_lexical_scope(&mut self,
1867 record_used_id: Option<NodeId>,
1869 -> Option<LexicalScopeBinding<'a>> {
1870 let record_used = record_used_id.is_some();
1871 assert!(ns == TypeNS || ns == ValueNS);
1873 ident.span = if ident.name == keywords::SelfType.name() {
1874 // FIXME(jseyfried) improve `Self` hygiene
1875 ident.span.with_ctxt(SyntaxContext::empty())
1880 ident = ident.modern_and_legacy();
1883 // Walk backwards up the ribs in scope.
1884 let mut module = self.graph_root;
1885 for i in (0 .. self.ribs[ns].len()).rev() {
1886 if let Some(def) = self.ribs[ns][i].bindings.get(&ident).cloned() {
1887 // The ident resolves to a type parameter or local variable.
1888 return Some(LexicalScopeBinding::Def(
1889 self.adjust_local_def(ns, i, def, record_used, path_span)
1893 module = match self.ribs[ns][i].kind {
1894 ModuleRibKind(module) => module,
1895 MacroDefinition(def) if def == self.macro_def(ident.span.ctxt()) => {
1896 // If an invocation of this macro created `ident`, give up on `ident`
1897 // and switch to `ident`'s source from the macro definition.
1898 ident.span.remove_mark();
1904 let item = self.resolve_ident_in_module_unadjusted(
1905 ModuleOrUniformRoot::Module(module),
1912 if let Ok(binding) = item {
1913 // The ident resolves to an item.
1914 return Some(LexicalScopeBinding::Item(binding));
1918 ModuleKind::Block(..) => {}, // We can see through blocks
1923 ident.span = ident.span.modern();
1924 let mut poisoned = None;
1926 let opt_module = if let Some(node_id) = record_used_id {
1927 self.hygienic_lexical_parent_with_compatibility_fallback(module, &mut ident.span,
1928 node_id, &mut poisoned)
1930 self.hygienic_lexical_parent(module, &mut ident.span)
1932 module = unwrap_or!(opt_module, break);
1933 let orig_current_module = self.current_module;
1934 self.current_module = module; // Lexical resolutions can never be a privacy error.
1935 let result = self.resolve_ident_in_module_unadjusted(
1936 ModuleOrUniformRoot::Module(module),
1943 self.current_module = orig_current_module;
1947 if let Some(node_id) = poisoned {
1948 self.session.buffer_lint_with_diagnostic(
1949 lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
1950 node_id, ident.span,
1951 &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
1952 lint::builtin::BuiltinLintDiagnostics::
1953 ProcMacroDeriveResolutionFallback(ident.span),
1956 return Some(LexicalScopeBinding::Item(binding))
1958 Err(Determined) => continue,
1959 Err(Undetermined) =>
1960 span_bug!(ident.span, "undetermined resolution during main resolution pass"),
1964 if !module.no_implicit_prelude {
1965 // `record_used` means that we don't try to load crates during speculative resolution
1966 if record_used && ns == TypeNS && self.extern_prelude.contains(&ident.name) {
1967 let crate_id = self.crate_loader.process_path_extern(ident.name, ident.span);
1968 let crate_root = self.get_module(DefId { krate: crate_id, index: CRATE_DEF_INDEX });
1969 self.populate_module_if_necessary(&crate_root);
1971 let binding = (crate_root, ty::Visibility::Public,
1972 ident.span, Mark::root()).to_name_binding(self.arenas);
1973 return Some(LexicalScopeBinding::Item(binding));
1975 if ns == TypeNS && is_known_tool(ident.name) {
1976 let binding = (Def::ToolMod, ty::Visibility::Public,
1977 ident.span, Mark::root()).to_name_binding(self.arenas);
1978 return Some(LexicalScopeBinding::Item(binding));
1980 if let Some(prelude) = self.prelude {
1981 if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
1982 ModuleOrUniformRoot::Module(prelude),
1989 return Some(LexicalScopeBinding::Item(binding));
1997 fn hygienic_lexical_parent(&mut self, module: Module<'a>, span: &mut Span)
1998 -> Option<Module<'a>> {
1999 if !module.expansion.is_descendant_of(span.ctxt().outer()) {
2000 return Some(self.macro_def_scope(span.remove_mark()));
2003 if let ModuleKind::Block(..) = module.kind {
2004 return Some(module.parent.unwrap());
2010 fn hygienic_lexical_parent_with_compatibility_fallback(&mut self, module: Module<'a>,
2011 span: &mut Span, node_id: NodeId,
2012 poisoned: &mut Option<NodeId>)
2013 -> Option<Module<'a>> {
2014 if let module @ Some(..) = self.hygienic_lexical_parent(module, span) {
2018 // We need to support the next case under a deprecation warning
2021 // ---- begin: this comes from a proc macro derive
2022 // mod implementation_details {
2023 // // Note that `MyStruct` is not in scope here.
2024 // impl SomeTrait for MyStruct { ... }
2028 // So we have to fall back to the module's parent during lexical resolution in this case.
2029 if let Some(parent) = module.parent {
2030 // Inner module is inside the macro, parent module is outside of the macro.
2031 if module.expansion != parent.expansion &&
2032 module.expansion.is_descendant_of(parent.expansion) {
2033 // The macro is a proc macro derive
2034 if module.expansion.looks_like_proc_macro_derive() {
2035 if parent.expansion.is_descendant_of(span.ctxt().outer()) {
2036 *poisoned = Some(node_id);
2037 return module.parent;
2046 fn resolve_ident_in_module(&mut self,
2047 module: ModuleOrUniformRoot<'a>,
2052 -> Result<&'a NameBinding<'a>, Determinacy> {
2053 ident.span = ident.span.modern();
2054 let orig_current_module = self.current_module;
2055 if let ModuleOrUniformRoot::Module(module) = module {
2056 if let Some(def) = ident.span.adjust(module.expansion) {
2057 self.current_module = self.macro_def_scope(def);
2060 let result = self.resolve_ident_in_module_unadjusted(
2061 module, ident, ns, false, record_used, span,
2063 self.current_module = orig_current_module;
2067 fn resolve_crate_root(&mut self, ident: Ident) -> Module<'a> {
2068 let mut ctxt = ident.span.ctxt();
2069 let mark = if ident.name == keywords::DollarCrate.name() {
2070 // When resolving `$crate` from a `macro_rules!` invoked in a `macro`,
2071 // we don't want to pretend that the `macro_rules!` definition is in the `macro`
2072 // as described in `SyntaxContext::apply_mark`, so we ignore prepended modern marks.
2073 // FIXME: This is only a guess and it doesn't work correctly for `macro_rules!`
2074 // definitions actually produced by `macro` and `macro` definitions produced by
2075 // `macro_rules!`, but at least such configurations are not stable yet.
2076 ctxt = ctxt.modern_and_legacy();
2077 let mut iter = ctxt.marks().into_iter().rev().peekable();
2078 let mut result = None;
2079 // Find the last modern mark from the end if it exists.
2080 while let Some(&(mark, transparency)) = iter.peek() {
2081 if transparency == Transparency::Opaque {
2082 result = Some(mark);
2088 // Then find the last legacy mark from the end if it exists.
2089 for (mark, transparency) in iter {
2090 if transparency == Transparency::SemiTransparent {
2091 result = Some(mark);
2098 ctxt = ctxt.modern();
2099 ctxt.adjust(Mark::root())
2101 let module = match mark {
2102 Some(def) => self.macro_def_scope(def),
2103 None => return self.graph_root,
2105 self.get_module(DefId { index: CRATE_DEF_INDEX, ..module.normal_ancestor_id })
2108 fn resolve_self(&mut self, ctxt: &mut SyntaxContext, module: Module<'a>) -> Module<'a> {
2109 let mut module = self.get_module(module.normal_ancestor_id);
2110 while module.span.ctxt().modern() != *ctxt {
2111 let parent = module.parent.unwrap_or_else(|| self.macro_def_scope(ctxt.remove_mark()));
2112 module = self.get_module(parent.normal_ancestor_id);
2119 // We maintain a list of value ribs and type ribs.
2121 // Simultaneously, we keep track of the current position in the module
2122 // graph in the `current_module` pointer. When we go to resolve a name in
2123 // the value or type namespaces, we first look through all the ribs and
2124 // then query the module graph. When we resolve a name in the module
2125 // namespace, we can skip all the ribs (since nested modules are not
2126 // allowed within blocks in Rust) and jump straight to the current module
2129 // Named implementations are handled separately. When we find a method
2130 // call, we consult the module node to find all of the implementations in
2131 // scope. This information is lazily cached in the module node. We then
2132 // generate a fake "implementation scope" containing all the
2133 // implementations thus found, for compatibility with old resolve pass.
2135 pub fn with_scope<F, T>(&mut self, id: NodeId, f: F) -> T
2136 where F: FnOnce(&mut Resolver) -> T
2138 let id = self.definitions.local_def_id(id);
2139 let module = self.module_map.get(&id).cloned(); // clones a reference
2140 if let Some(module) = module {
2141 // Move down in the graph.
2142 let orig_module = replace(&mut self.current_module, module);
2143 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(module)));
2144 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(module)));
2146 self.finalize_current_module_macro_resolutions();
2149 self.current_module = orig_module;
2150 self.ribs[ValueNS].pop();
2151 self.ribs[TypeNS].pop();
2158 /// Searches the current set of local scopes for labels. Returns the first non-None label that
2159 /// is returned by the given predicate function
2161 /// Stops after meeting a closure.
2162 fn search_label<P, R>(&self, mut ident: Ident, pred: P) -> Option<R>
2163 where P: Fn(&Rib, Ident) -> Option<R>
2165 for rib in self.label_ribs.iter().rev() {
2168 // If an invocation of this macro created `ident`, give up on `ident`
2169 // and switch to `ident`'s source from the macro definition.
2170 MacroDefinition(def) => {
2171 if def == self.macro_def(ident.span.ctxt()) {
2172 ident.span.remove_mark();
2176 // Do not resolve labels across function boundary
2180 let r = pred(rib, ident);
2188 fn resolve_adt(&mut self, item: &Item, generics: &Generics) {
2189 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2190 let item_def_id = this.definitions.local_def_id(item.id);
2191 if this.session.features_untracked().self_in_typedefs {
2192 this.with_self_rib(Def::SelfTy(None, Some(item_def_id)), |this| {
2193 visit::walk_item(this, item);
2196 visit::walk_item(this, item);
2201 fn resolve_item(&mut self, item: &Item) {
2202 let name = item.ident.name;
2203 debug!("(resolving item) resolving {}", name);
2206 ItemKind::Ty(_, ref generics) |
2207 ItemKind::Fn(_, _, ref generics, _) |
2208 ItemKind::Existential(_, ref generics) => {
2209 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind),
2210 |this| visit::walk_item(this, item));
2213 ItemKind::Enum(_, ref generics) |
2214 ItemKind::Struct(_, ref generics) |
2215 ItemKind::Union(_, ref generics) => {
2216 self.resolve_adt(item, generics);
2219 ItemKind::Impl(.., ref generics, ref opt_trait_ref, ref self_type, ref impl_items) =>
2220 self.resolve_implementation(generics,
2226 ItemKind::Trait(.., ref generics, ref bounds, ref trait_items) => {
2227 // Create a new rib for the trait-wide type parameters.
2228 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2229 let local_def_id = this.definitions.local_def_id(item.id);
2230 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2231 this.visit_generics(generics);
2232 walk_list!(this, visit_param_bound, bounds);
2234 for trait_item in trait_items {
2235 let type_parameters = HasTypeParameters(&trait_item.generics,
2236 TraitOrImplItemRibKind);
2237 this.with_type_parameter_rib(type_parameters, |this| {
2238 match trait_item.node {
2239 TraitItemKind::Const(ref ty, ref default) => {
2242 // Only impose the restrictions of
2243 // ConstRibKind for an actual constant
2244 // expression in a provided default.
2245 if let Some(ref expr) = *default{
2246 this.with_constant_rib(|this| {
2247 this.visit_expr(expr);
2251 TraitItemKind::Method(_, _) => {
2252 visit::walk_trait_item(this, trait_item)
2254 TraitItemKind::Type(..) => {
2255 visit::walk_trait_item(this, trait_item)
2257 TraitItemKind::Macro(_) => {
2258 panic!("unexpanded macro in resolve!")
2267 ItemKind::TraitAlias(ref generics, ref bounds) => {
2268 // Create a new rib for the trait-wide type parameters.
2269 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2270 let local_def_id = this.definitions.local_def_id(item.id);
2271 this.with_self_rib(Def::SelfTy(Some(local_def_id), None), |this| {
2272 this.visit_generics(generics);
2273 walk_list!(this, visit_param_bound, bounds);
2278 ItemKind::Mod(_) | ItemKind::ForeignMod(_) => {
2279 self.with_scope(item.id, |this| {
2280 visit::walk_item(this, item);
2284 ItemKind::Static(ref ty, _, ref expr) |
2285 ItemKind::Const(ref ty, ref expr) => {
2286 self.with_item_rib(|this| {
2288 this.with_constant_rib(|this| {
2289 this.visit_expr(expr);
2294 ItemKind::Use(ref use_tree) => {
2295 // Imports are resolved as global by default, add starting root segment.
2297 segments: use_tree.prefix.make_root().into_iter().collect(),
2298 span: use_tree.span,
2300 self.resolve_use_tree(item.id, use_tree.span, item.id, use_tree, &path);
2303 ItemKind::ExternCrate(_) | ItemKind::MacroDef(..) | ItemKind::GlobalAsm(_) => {
2304 // do nothing, these are just around to be encoded
2307 ItemKind::Mac(_) => panic!("unexpanded macro in resolve!"),
2311 /// For the most part, use trees are desugared into `ImportDirective` instances
2312 /// when building the reduced graph (see `build_reduced_graph_for_use_tree`). But
2313 /// there is one special case we handle here: an empty nested import like
2314 /// `a::{b::{}}`, which desugares into...no import directives.
2315 fn resolve_use_tree(
2320 use_tree: &ast::UseTree,
2323 match use_tree.kind {
2324 ast::UseTreeKind::Nested(ref items) => {
2326 segments: prefix.segments
2328 .chain(use_tree.prefix.segments.iter())
2331 span: prefix.span.to(use_tree.prefix.span),
2334 if items.len() == 0 {
2335 // Resolve prefix of an import with empty braces (issue #28388).
2336 self.smart_resolve_path_with_crate_lint(
2340 PathSource::ImportPrefix,
2341 CrateLint::UsePath { root_id, root_span },
2344 for &(ref tree, nested_id) in items {
2345 self.resolve_use_tree(root_id, root_span, nested_id, tree, &path);
2349 ast::UseTreeKind::Simple(..) => {},
2350 ast::UseTreeKind::Glob => {},
2354 fn with_type_parameter_rib<'b, F>(&'b mut self, type_parameters: TypeParameters<'a, 'b>, f: F)
2355 where F: FnOnce(&mut Resolver)
2357 match type_parameters {
2358 HasTypeParameters(generics, rib_kind) => {
2359 let mut function_type_rib = Rib::new(rib_kind);
2360 let mut seen_bindings = FxHashMap();
2361 for param in &generics.params {
2363 GenericParamKind::Lifetime { .. } => {}
2364 GenericParamKind::Type { .. } => {
2365 let ident = param.ident.modern();
2366 debug!("with_type_parameter_rib: {}", param.id);
2368 if seen_bindings.contains_key(&ident) {
2369 let span = seen_bindings.get(&ident).unwrap();
2370 let err = ResolutionError::NameAlreadyUsedInTypeParameterList(
2374 resolve_error(self, param.ident.span, err);
2376 seen_bindings.entry(ident).or_insert(param.ident.span);
2378 // Plain insert (no renaming).
2379 let def = Def::TyParam(self.definitions.local_def_id(param.id));
2380 function_type_rib.bindings.insert(ident, def);
2381 self.record_def(param.id, PathResolution::new(def));
2385 self.ribs[TypeNS].push(function_type_rib);
2388 NoTypeParameters => {
2395 if let HasTypeParameters(..) = type_parameters {
2396 self.ribs[TypeNS].pop();
2400 fn with_label_rib<F>(&mut self, f: F)
2401 where F: FnOnce(&mut Resolver)
2403 self.label_ribs.push(Rib::new(NormalRibKind));
2405 self.label_ribs.pop();
2408 fn with_item_rib<F>(&mut self, f: F)
2409 where F: FnOnce(&mut Resolver)
2411 self.ribs[ValueNS].push(Rib::new(ItemRibKind));
2412 self.ribs[TypeNS].push(Rib::new(ItemRibKind));
2414 self.ribs[TypeNS].pop();
2415 self.ribs[ValueNS].pop();
2418 fn with_constant_rib<F>(&mut self, f: F)
2419 where F: FnOnce(&mut Resolver)
2421 self.ribs[ValueNS].push(Rib::new(ConstantItemRibKind));
2422 self.label_ribs.push(Rib::new(ConstantItemRibKind));
2424 self.label_ribs.pop();
2425 self.ribs[ValueNS].pop();
2428 fn with_current_self_type<T, F>(&mut self, self_type: &Ty, f: F) -> T
2429 where F: FnOnce(&mut Resolver) -> T
2431 // Handle nested impls (inside fn bodies)
2432 let previous_value = replace(&mut self.current_self_type, Some(self_type.clone()));
2433 let result = f(self);
2434 self.current_self_type = previous_value;
2438 /// This is called to resolve a trait reference from an `impl` (i.e. `impl Trait for Foo`)
2439 fn with_optional_trait_ref<T, F>(&mut self, opt_trait_ref: Option<&TraitRef>, f: F) -> T
2440 where F: FnOnce(&mut Resolver, Option<DefId>) -> T
2442 let mut new_val = None;
2443 let mut new_id = None;
2444 if let Some(trait_ref) = opt_trait_ref {
2445 let path: Vec<_> = trait_ref.path.segments.iter()
2446 .map(|seg| seg.ident)
2448 let def = self.smart_resolve_path_fragment(
2452 trait_ref.path.span,
2453 PathSource::Trait(AliasPossibility::No),
2454 CrateLint::SimplePath(trait_ref.ref_id),
2456 if def != Def::Err {
2457 new_id = Some(def.def_id());
2458 let span = trait_ref.path.span;
2459 if let PathResult::Module(ModuleOrUniformRoot::Module(module)) =
2466 CrateLint::SimplePath(trait_ref.ref_id),
2469 new_val = Some((module, trait_ref.clone()));
2473 let original_trait_ref = replace(&mut self.current_trait_ref, new_val);
2474 let result = f(self, new_id);
2475 self.current_trait_ref = original_trait_ref;
2479 fn with_self_rib<F>(&mut self, self_def: Def, f: F)
2480 where F: FnOnce(&mut Resolver)
2482 let mut self_type_rib = Rib::new(NormalRibKind);
2484 // plain insert (no renaming, types are not currently hygienic....)
2485 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2486 self.ribs[TypeNS].push(self_type_rib);
2488 self.ribs[TypeNS].pop();
2491 fn with_self_struct_ctor_rib<F>(&mut self, impl_id: DefId, f: F)
2492 where F: FnOnce(&mut Resolver)
2494 let self_def = Def::SelfCtor(impl_id);
2495 let mut self_type_rib = Rib::new(NormalRibKind);
2496 self_type_rib.bindings.insert(keywords::SelfType.ident(), self_def);
2497 self.ribs[ValueNS].push(self_type_rib);
2499 self.ribs[ValueNS].pop();
2502 fn resolve_implementation(&mut self,
2503 generics: &Generics,
2504 opt_trait_reference: &Option<TraitRef>,
2507 impl_items: &[ImplItem]) {
2508 // If applicable, create a rib for the type parameters.
2509 self.with_type_parameter_rib(HasTypeParameters(generics, ItemRibKind), |this| {
2510 // Dummy self type for better errors if `Self` is used in the trait path.
2511 this.with_self_rib(Def::SelfTy(None, None), |this| {
2512 // Resolve the trait reference, if necessary.
2513 this.with_optional_trait_ref(opt_trait_reference.as_ref(), |this, trait_id| {
2514 let item_def_id = this.definitions.local_def_id(item_id);
2515 this.with_self_rib(Def::SelfTy(trait_id, Some(item_def_id)), |this| {
2516 if let Some(trait_ref) = opt_trait_reference.as_ref() {
2517 // Resolve type arguments in the trait path.
2518 visit::walk_trait_ref(this, trait_ref);
2520 // Resolve the self type.
2521 this.visit_ty(self_type);
2522 // Resolve the type parameters.
2523 this.visit_generics(generics);
2524 // Resolve the items within the impl.
2525 this.with_current_self_type(self_type, |this| {
2526 this.with_self_struct_ctor_rib(item_def_id, |this| {
2527 for impl_item in impl_items {
2528 this.resolve_visibility(&impl_item.vis);
2530 // We also need a new scope for the impl item type parameters.
2531 let type_parameters = HasTypeParameters(&impl_item.generics,
2532 TraitOrImplItemRibKind);
2533 this.with_type_parameter_rib(type_parameters, |this| {
2534 use self::ResolutionError::*;
2535 match impl_item.node {
2536 ImplItemKind::Const(..) => {
2537 // If this is a trait impl, ensure the const
2539 this.check_trait_item(impl_item.ident,
2542 |n, s| ConstNotMemberOfTrait(n, s));
2543 this.with_constant_rib(|this|
2544 visit::walk_impl_item(this, impl_item)
2547 ImplItemKind::Method(..) => {
2548 // If this is a trait impl, ensure the method
2550 this.check_trait_item(impl_item.ident,
2553 |n, s| MethodNotMemberOfTrait(n, s));
2555 visit::walk_impl_item(this, impl_item);
2557 ImplItemKind::Type(ref ty) => {
2558 // If this is a trait impl, ensure the type
2560 this.check_trait_item(impl_item.ident,
2563 |n, s| TypeNotMemberOfTrait(n, s));
2567 ImplItemKind::Existential(ref bounds) => {
2568 // If this is a trait impl, ensure the type
2570 this.check_trait_item(impl_item.ident,
2573 |n, s| TypeNotMemberOfTrait(n, s));
2575 for bound in bounds {
2576 this.visit_param_bound(bound);
2579 ImplItemKind::Macro(_) =>
2580 panic!("unexpanded macro in resolve!"),
2592 fn check_trait_item<F>(&mut self, ident: Ident, ns: Namespace, span: Span, err: F)
2593 where F: FnOnce(Name, &str) -> ResolutionError
2595 // If there is a TraitRef in scope for an impl, then the method must be in the
2597 if let Some((module, _)) = self.current_trait_ref {
2598 if self.resolve_ident_in_module(
2599 ModuleOrUniformRoot::Module(module),
2605 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
2606 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
2611 fn resolve_local(&mut self, local: &Local) {
2612 // Resolve the type.
2613 walk_list!(self, visit_ty, &local.ty);
2615 // Resolve the initializer.
2616 walk_list!(self, visit_expr, &local.init);
2618 // Resolve the pattern.
2619 self.resolve_pattern(&local.pat, PatternSource::Let, &mut FxHashMap());
2622 // build a map from pattern identifiers to binding-info's.
2623 // this is done hygienically. This could arise for a macro
2624 // that expands into an or-pattern where one 'x' was from the
2625 // user and one 'x' came from the macro.
2626 fn binding_mode_map(&mut self, pat: &Pat) -> BindingMap {
2627 let mut binding_map = FxHashMap();
2629 pat.walk(&mut |pat| {
2630 if let PatKind::Ident(binding_mode, ident, ref sub_pat) = pat.node {
2631 if sub_pat.is_some() || match self.def_map.get(&pat.id).map(|res| res.base_def()) {
2632 Some(Def::Local(..)) => true,
2635 let binding_info = BindingInfo { span: ident.span, binding_mode: binding_mode };
2636 binding_map.insert(ident, binding_info);
2645 // check that all of the arms in an or-pattern have exactly the
2646 // same set of bindings, with the same binding modes for each.
2647 fn check_consistent_bindings(&mut self, pats: &[P<Pat>]) {
2648 if pats.is_empty() {
2652 let mut missing_vars = FxHashMap();
2653 let mut inconsistent_vars = FxHashMap();
2654 for (i, p) in pats.iter().enumerate() {
2655 let map_i = self.binding_mode_map(&p);
2657 for (j, q) in pats.iter().enumerate() {
2662 let map_j = self.binding_mode_map(&q);
2663 for (&key, &binding_i) in &map_i {
2664 if map_j.len() == 0 { // Account for missing bindings when
2665 let binding_error = missing_vars // map_j has none.
2667 .or_insert(BindingError {
2669 origin: BTreeSet::new(),
2670 target: BTreeSet::new(),
2672 binding_error.origin.insert(binding_i.span);
2673 binding_error.target.insert(q.span);
2675 for (&key_j, &binding_j) in &map_j {
2676 match map_i.get(&key_j) {
2677 None => { // missing binding
2678 let binding_error = missing_vars
2680 .or_insert(BindingError {
2682 origin: BTreeSet::new(),
2683 target: BTreeSet::new(),
2685 binding_error.origin.insert(binding_j.span);
2686 binding_error.target.insert(p.span);
2688 Some(binding_i) => { // check consistent binding
2689 if binding_i.binding_mode != binding_j.binding_mode {
2692 .or_insert((binding_j.span, binding_i.span));
2700 let mut missing_vars = missing_vars.iter().collect::<Vec<_>>();
2701 missing_vars.sort();
2702 for (_, v) in missing_vars {
2704 *v.origin.iter().next().unwrap(),
2705 ResolutionError::VariableNotBoundInPattern(v));
2707 let mut inconsistent_vars = inconsistent_vars.iter().collect::<Vec<_>>();
2708 inconsistent_vars.sort();
2709 for (name, v) in inconsistent_vars {
2710 resolve_error(self, v.0, ResolutionError::VariableBoundWithDifferentMode(*name, v.1));
2714 fn resolve_arm(&mut self, arm: &Arm) {
2715 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2717 let mut bindings_list = FxHashMap();
2718 for pattern in &arm.pats {
2719 self.resolve_pattern(&pattern, PatternSource::Match, &mut bindings_list);
2722 // This has to happen *after* we determine which pat_idents are variants
2723 self.check_consistent_bindings(&arm.pats);
2726 Some(ast::Guard::If(ref expr)) => self.visit_expr(expr),
2729 self.visit_expr(&arm.body);
2731 self.ribs[ValueNS].pop();
2734 fn resolve_block(&mut self, block: &Block) {
2735 debug!("(resolving block) entering block");
2736 // Move down in the graph, if there's an anonymous module rooted here.
2737 let orig_module = self.current_module;
2738 let anonymous_module = self.block_map.get(&block.id).cloned(); // clones a reference
2740 let mut num_macro_definition_ribs = 0;
2741 if let Some(anonymous_module) = anonymous_module {
2742 debug!("(resolving block) found anonymous module, moving down");
2743 self.ribs[ValueNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2744 self.ribs[TypeNS].push(Rib::new(ModuleRibKind(anonymous_module)));
2745 self.current_module = anonymous_module;
2746 self.finalize_current_module_macro_resolutions();
2748 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
2751 // Descend into the block.
2752 for stmt in &block.stmts {
2753 if let ast::StmtKind::Item(ref item) = stmt.node {
2754 if let ast::ItemKind::MacroDef(..) = item.node {
2755 num_macro_definition_ribs += 1;
2756 let def = self.definitions.local_def_id(item.id);
2757 self.ribs[ValueNS].push(Rib::new(MacroDefinition(def)));
2758 self.label_ribs.push(Rib::new(MacroDefinition(def)));
2762 self.visit_stmt(stmt);
2766 self.current_module = orig_module;
2767 for _ in 0 .. num_macro_definition_ribs {
2768 self.ribs[ValueNS].pop();
2769 self.label_ribs.pop();
2771 self.ribs[ValueNS].pop();
2772 if anonymous_module.is_some() {
2773 self.ribs[TypeNS].pop();
2775 debug!("(resolving block) leaving block");
2778 fn fresh_binding(&mut self,
2781 outer_pat_id: NodeId,
2782 pat_src: PatternSource,
2783 bindings: &mut FxHashMap<Ident, NodeId>)
2785 // Add the binding to the local ribs, if it
2786 // doesn't already exist in the bindings map. (We
2787 // must not add it if it's in the bindings map
2788 // because that breaks the assumptions later
2789 // passes make about or-patterns.)
2790 let ident = ident.modern_and_legacy();
2791 let mut def = Def::Local(pat_id);
2792 match bindings.get(&ident).cloned() {
2793 Some(id) if id == outer_pat_id => {
2794 // `Variant(a, a)`, error
2798 ResolutionError::IdentifierBoundMoreThanOnceInSamePattern(
2802 Some(..) if pat_src == PatternSource::FnParam => {
2803 // `fn f(a: u8, a: u8)`, error
2807 ResolutionError::IdentifierBoundMoreThanOnceInParameterList(
2811 Some(..) if pat_src == PatternSource::Match ||
2812 pat_src == PatternSource::IfLet ||
2813 pat_src == PatternSource::WhileLet => {
2814 // `Variant1(a) | Variant2(a)`, ok
2815 // Reuse definition from the first `a`.
2816 def = self.ribs[ValueNS].last_mut().unwrap().bindings[&ident];
2819 span_bug!(ident.span, "two bindings with the same name from \
2820 unexpected pattern source {:?}", pat_src);
2823 // A completely fresh binding, add to the lists if it's valid.
2824 if ident.name != keywords::Invalid.name() {
2825 bindings.insert(ident, outer_pat_id);
2826 self.ribs[ValueNS].last_mut().unwrap().bindings.insert(ident, def);
2831 PathResolution::new(def)
2834 fn resolve_pattern(&mut self,
2836 pat_src: PatternSource,
2837 // Maps idents to the node ID for the
2838 // outermost pattern that binds them.
2839 bindings: &mut FxHashMap<Ident, NodeId>) {
2840 // Visit all direct subpatterns of this pattern.
2841 let outer_pat_id = pat.id;
2842 pat.walk(&mut |pat| {
2844 PatKind::Ident(bmode, ident, ref opt_pat) => {
2845 // First try to resolve the identifier as some existing
2846 // entity, then fall back to a fresh binding.
2847 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS,
2849 .and_then(LexicalScopeBinding::item);
2850 let resolution = binding.map(NameBinding::def).and_then(|def| {
2851 let is_syntactic_ambiguity = opt_pat.is_none() &&
2852 bmode == BindingMode::ByValue(Mutability::Immutable);
2854 Def::StructCtor(_, CtorKind::Const) |
2855 Def::VariantCtor(_, CtorKind::Const) |
2856 Def::Const(..) if is_syntactic_ambiguity => {
2857 // Disambiguate in favor of a unit struct/variant
2858 // or constant pattern.
2859 self.record_use(ident, ValueNS, binding.unwrap());
2860 Some(PathResolution::new(def))
2862 Def::StructCtor(..) | Def::VariantCtor(..) |
2863 Def::Const(..) | Def::Static(..) => {
2864 // This is unambiguously a fresh binding, either syntactically
2865 // (e.g. `IDENT @ PAT` or `ref IDENT`) or because `IDENT` resolves
2866 // to something unusable as a pattern (e.g. constructor function),
2867 // but we still conservatively report an error, see
2868 // issues/33118#issuecomment-233962221 for one reason why.
2872 ResolutionError::BindingShadowsSomethingUnacceptable(
2873 pat_src.descr(), ident.name, binding.unwrap())
2877 Def::Fn(..) | Def::Err => {
2878 // These entities are explicitly allowed
2879 // to be shadowed by fresh bindings.
2883 span_bug!(ident.span, "unexpected definition for an \
2884 identifier in pattern: {:?}", def);
2887 }).unwrap_or_else(|| {
2888 self.fresh_binding(ident, pat.id, outer_pat_id, pat_src, bindings)
2891 self.record_def(pat.id, resolution);
2894 PatKind::TupleStruct(ref path, ..) => {
2895 self.smart_resolve_path(pat.id, None, path, PathSource::TupleStruct);
2898 PatKind::Path(ref qself, ref path) => {
2899 self.smart_resolve_path(pat.id, qself.as_ref(), path, PathSource::Pat);
2902 PatKind::Struct(ref path, ..) => {
2903 self.smart_resolve_path(pat.id, None, path, PathSource::Struct);
2911 visit::walk_pat(self, pat);
2914 // High-level and context dependent path resolution routine.
2915 // Resolves the path and records the resolution into definition map.
2916 // If resolution fails tries several techniques to find likely
2917 // resolution candidates, suggest imports or other help, and report
2918 // errors in user friendly way.
2919 fn smart_resolve_path(&mut self,
2921 qself: Option<&QSelf>,
2925 self.smart_resolve_path_with_crate_lint(id, qself, path, source, CrateLint::SimplePath(id))
2928 /// A variant of `smart_resolve_path` where you also specify extra
2929 /// information about where the path came from; this extra info is
2930 /// sometimes needed for the lint that recommends rewriting
2931 /// absolute paths to `crate`, so that it knows how to frame the
2932 /// suggestion. If you are just resolving a path like `foo::bar`
2933 /// that appears...somewhere, though, then you just want
2934 /// `CrateLint::SimplePath`, which is what `smart_resolve_path`
2935 /// already provides.
2936 fn smart_resolve_path_with_crate_lint(
2939 qself: Option<&QSelf>,
2942 crate_lint: CrateLint
2943 ) -> PathResolution {
2944 let segments = &path.segments.iter()
2945 .map(|seg| seg.ident)
2946 .collect::<Vec<_>>();
2947 self.smart_resolve_path_fragment(id, qself, segments, path.span, source, crate_lint)
2950 fn smart_resolve_path_fragment(&mut self,
2952 qself: Option<&QSelf>,
2956 crate_lint: CrateLint)
2958 let ident_span = path.last().map_or(span, |ident| ident.span);
2959 let ns = source.namespace();
2960 let is_expected = &|def| source.is_expected(def);
2961 let is_enum_variant = &|def| if let Def::Variant(..) = def { true } else { false };
2963 // Base error is amended with one short label and possibly some longer helps/notes.
2964 let report_errors = |this: &mut Self, def: Option<Def>| {
2965 // Make the base error.
2966 let expected = source.descr_expected();
2967 let path_str = names_to_string(path);
2968 let code = source.error_code(def.is_some());
2969 let (base_msg, fallback_label, base_span) = if let Some(def) = def {
2970 (format!("expected {}, found {} `{}`", expected, def.kind_name(), path_str),
2971 format!("not a {}", expected),
2974 let item_str = path[path.len() - 1];
2975 let item_span = path[path.len() - 1].span;
2976 let (mod_prefix, mod_str) = if path.len() == 1 {
2977 (String::new(), "this scope".to_string())
2978 } else if path.len() == 2 && path[0].name == keywords::CrateRoot.name() {
2979 (String::new(), "the crate root".to_string())
2981 let mod_path = &path[..path.len() - 1];
2982 let mod_prefix = match this.resolve_path(None, mod_path, Some(TypeNS),
2983 false, span, CrateLint::No) {
2984 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
2987 }.map_or(String::new(), |def| format!("{} ", def.kind_name()));
2988 (mod_prefix, format!("`{}`", names_to_string(mod_path)))
2990 (format!("cannot find {} `{}` in {}{}", expected, item_str, mod_prefix, mod_str),
2991 format!("not found in {}", mod_str),
2994 let code = DiagnosticId::Error(code.into());
2995 let mut err = this.session.struct_span_err_with_code(base_span, &base_msg, code);
2997 // Emit special messages for unresolved `Self` and `self`.
2998 if is_self_type(path, ns) {
2999 __diagnostic_used!(E0411);
3000 err.code(DiagnosticId::Error("E0411".into()));
3001 let available_in = if this.session.features_untracked().self_in_typedefs {
3002 "impls, traits, and type definitions"
3006 err.span_label(span, format!("`Self` is only available in {}", available_in));
3007 return (err, Vec::new());
3009 if is_self_value(path, ns) {
3010 __diagnostic_used!(E0424);
3011 err.code(DiagnosticId::Error("E0424".into()));
3012 err.span_label(span, format!("`self` value is only available in \
3013 methods with `self` parameter"));
3014 return (err, Vec::new());
3017 // Try to lookup the name in more relaxed fashion for better error reporting.
3018 let ident = *path.last().unwrap();
3019 let candidates = this.lookup_import_candidates(ident.name, ns, is_expected);
3020 if candidates.is_empty() && is_expected(Def::Enum(DefId::local(CRATE_DEF_INDEX))) {
3021 let enum_candidates =
3022 this.lookup_import_candidates(ident.name, ns, is_enum_variant);
3023 let mut enum_candidates = enum_candidates.iter()
3024 .map(|suggestion| import_candidate_to_paths(&suggestion)).collect::<Vec<_>>();
3025 enum_candidates.sort();
3026 for (sp, variant_path, enum_path) in enum_candidates {
3028 let msg = format!("there is an enum variant `{}`, \
3034 err.span_suggestion_with_applicability(
3036 "you can try using the variant's enum",
3038 Applicability::MachineApplicable,
3043 if path.len() == 1 && this.self_type_is_available(span) {
3044 if let Some(candidate) = this.lookup_assoc_candidate(ident, ns, is_expected) {
3045 let self_is_available = this.self_value_is_available(path[0].span, span);
3047 AssocSuggestion::Field => {
3048 err.span_suggestion_with_applicability(
3051 format!("self.{}", path_str),
3052 Applicability::MachineApplicable,
3054 if !self_is_available {
3055 err.span_label(span, format!("`self` value is only available in \
3056 methods with `self` parameter"));
3059 AssocSuggestion::MethodWithSelf if self_is_available => {
3060 err.span_suggestion_with_applicability(
3063 format!("self.{}", path_str),
3064 Applicability::MachineApplicable,
3067 AssocSuggestion::MethodWithSelf | AssocSuggestion::AssocItem => {
3068 err.span_suggestion_with_applicability(
3071 format!("Self::{}", path_str),
3072 Applicability::MachineApplicable,
3076 return (err, candidates);
3080 let mut levenshtein_worked = false;
3083 if let Some(candidate) = this.lookup_typo_candidate(path, ns, is_expected, span) {
3084 err.span_label(ident_span, format!("did you mean `{}`?", candidate));
3085 levenshtein_worked = true;
3088 // Try context dependent help if relaxed lookup didn't work.
3089 if let Some(def) = def {
3090 match (def, source) {
3091 (Def::Macro(..), _) => {
3092 err.span_label(span, format!("did you mean `{}!(...)`?", path_str));
3093 return (err, candidates);
3095 (Def::TyAlias(..), PathSource::Trait(_)) => {
3096 err.span_label(span, "type aliases cannot be used for traits");
3097 return (err, candidates);
3099 (Def::Mod(..), PathSource::Expr(Some(parent))) => match parent.node {
3100 ExprKind::Field(_, ident) => {
3101 err.span_label(parent.span, format!("did you mean `{}::{}`?",
3103 return (err, candidates);
3105 ExprKind::MethodCall(ref segment, ..) => {
3106 err.span_label(parent.span, format!("did you mean `{}::{}(...)`?",
3107 path_str, segment.ident));
3108 return (err, candidates);
3112 (Def::Enum(..), PathSource::TupleStruct)
3113 | (Def::Enum(..), PathSource::Expr(..)) => {
3114 if let Some(variants) = this.collect_enum_variants(def) {
3115 err.note(&format!("did you mean to use one \
3116 of the following variants?\n{}",
3118 .map(|suggestion| path_names_to_string(suggestion))
3119 .map(|suggestion| format!("- `{}`", suggestion))
3120 .collect::<Vec<_>>()
3124 err.note("did you mean to use one of the enum's variants?");
3126 return (err, candidates);
3128 (Def::Struct(def_id), _) if ns == ValueNS => {
3129 if let Some((ctor_def, ctor_vis))
3130 = this.struct_constructors.get(&def_id).cloned() {
3131 let accessible_ctor = this.is_accessible(ctor_vis);
3132 if is_expected(ctor_def) && !accessible_ctor {
3133 err.span_label(span, format!("constructor is not visible \
3134 here due to private fields"));
3137 // HACK(estebank): find a better way to figure out that this was a
3138 // parser issue where a struct literal is being used on an expression
3139 // where a brace being opened means a block is being started. Look
3140 // ahead for the next text to see if `span` is followed by a `{`.
3141 let cm = this.session.source_map();
3144 sp = cm.next_point(sp);
3145 match cm.span_to_snippet(sp) {
3146 Ok(ref snippet) => {
3147 if snippet.chars().any(|c| { !c.is_whitespace() }) {
3154 let followed_by_brace = match cm.span_to_snippet(sp) {
3155 Ok(ref snippet) if snippet == "{" => true,
3158 if let (PathSource::Expr(None), true) = (source, followed_by_brace) {
3161 format!("did you mean `({} {{ /* fields */ }})`?", path_str),
3166 format!("did you mean `{} {{ /* fields */ }}`?", path_str),
3170 return (err, candidates);
3172 (Def::Union(..), _) |
3173 (Def::Variant(..), _) |
3174 (Def::VariantCtor(_, CtorKind::Fictive), _) if ns == ValueNS => {
3175 err.span_label(span, format!("did you mean `{} {{ /* fields */ }}`?",
3177 return (err, candidates);
3179 (Def::SelfTy(..), _) if ns == ValueNS => {
3180 err.span_label(span, fallback_label);
3181 err.note("can't use `Self` as a constructor, you must use the \
3182 implemented struct");
3183 return (err, candidates);
3185 (Def::TyAlias(_), _) | (Def::AssociatedTy(..), _) if ns == ValueNS => {
3186 err.note("can't use a type alias as a constructor");
3187 return (err, candidates);
3194 if !levenshtein_worked {
3195 err.span_label(base_span, fallback_label);
3196 this.type_ascription_suggestion(&mut err, base_span);
3200 let report_errors = |this: &mut Self, def: Option<Def>| {
3201 let (err, candidates) = report_errors(this, def);
3202 let def_id = this.current_module.normal_ancestor_id;
3203 let node_id = this.definitions.as_local_node_id(def_id).unwrap();
3204 let better = def.is_some();
3205 this.use_injections.push(UseError { err, candidates, node_id, better });
3206 err_path_resolution()
3209 let resolution = match self.resolve_qpath_anywhere(
3215 source.defer_to_typeck(),
3216 source.global_by_default(),
3219 Some(resolution) if resolution.unresolved_segments() == 0 => {
3220 if is_expected(resolution.base_def()) || resolution.base_def() == Def::Err {
3223 // Add a temporary hack to smooth the transition to new struct ctor
3224 // visibility rules. See #38932 for more details.
3226 if let Def::Struct(def_id) = resolution.base_def() {
3227 if let Some((ctor_def, ctor_vis))
3228 = self.struct_constructors.get(&def_id).cloned() {
3229 if is_expected(ctor_def) && self.is_accessible(ctor_vis) {
3230 let lint = lint::builtin::LEGACY_CONSTRUCTOR_VISIBILITY;
3231 self.session.buffer_lint(lint, id, span,
3232 "private struct constructors are not usable through \
3233 re-exports in outer modules",
3235 res = Some(PathResolution::new(ctor_def));
3240 res.unwrap_or_else(|| report_errors(self, Some(resolution.base_def())))
3243 Some(resolution) if source.defer_to_typeck() => {
3244 // Not fully resolved associated item `T::A::B` or `<T as Tr>::A::B`
3245 // or `<T>::A::B`. If `B` should be resolved in value namespace then
3246 // it needs to be added to the trait map.
3248 let item_name = *path.last().unwrap();
3249 let traits = self.get_traits_containing_item(item_name, ns);
3250 self.trait_map.insert(id, traits);
3254 _ => report_errors(self, None)
3257 if let PathSource::TraitItem(..) = source {} else {
3258 // Avoid recording definition of `A::B` in `<T as A>::B::C`.
3259 self.record_def(id, resolution);
3264 fn type_ascription_suggestion(&self,
3265 err: &mut DiagnosticBuilder,
3267 debug!("type_ascription_suggetion {:?}", base_span);
3268 let cm = self.session.source_map();
3269 debug!("self.current_type_ascription {:?}", self.current_type_ascription);
3270 if let Some(sp) = self.current_type_ascription.last() {
3272 loop { // try to find the `:`, bail on first non-':'/non-whitespace
3273 sp = cm.next_point(sp);
3274 if let Ok(snippet) = cm.span_to_snippet(sp.to(cm.next_point(sp))) {
3275 debug!("snippet {:?}", snippet);
3276 let line_sp = cm.lookup_char_pos(sp.hi()).line;
3277 let line_base_sp = cm.lookup_char_pos(base_span.lo()).line;
3278 debug!("{:?} {:?}", line_sp, line_base_sp);
3280 err.span_label(base_span,
3281 "expecting a type here because of type ascription");
3282 if line_sp != line_base_sp {
3283 err.span_suggestion_short_with_applicability(
3285 "did you mean to use `;` here instead?",
3287 Applicability::MaybeIncorrect,
3291 } else if snippet.trim().len() != 0 {
3292 debug!("tried to find type ascription `:` token, couldn't find it");
3302 fn self_type_is_available(&mut self, span: Span) -> bool {
3303 let binding = self.resolve_ident_in_lexical_scope(keywords::SelfType.ident(),
3304 TypeNS, None, span);
3305 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3308 fn self_value_is_available(&mut self, self_span: Span, path_span: Span) -> bool {
3309 let ident = Ident::new(keywords::SelfValue.name(), self_span);
3310 let binding = self.resolve_ident_in_lexical_scope(ident, ValueNS, None, path_span);
3311 if let Some(LexicalScopeBinding::Def(def)) = binding { def != Def::Err } else { false }
3314 // Resolve in alternative namespaces if resolution in the primary namespace fails.
3315 fn resolve_qpath_anywhere(&mut self,
3317 qself: Option<&QSelf>,
3319 primary_ns: Namespace,
3321 defer_to_typeck: bool,
3322 global_by_default: bool,
3323 crate_lint: CrateLint)
3324 -> Option<PathResolution> {
3325 let mut fin_res = None;
3326 // FIXME: can't resolve paths in macro namespace yet, macros are
3327 // processed by the little special hack below.
3328 for (i, ns) in [primary_ns, TypeNS, ValueNS, /*MacroNS*/].iter().cloned().enumerate() {
3329 if i == 0 || ns != primary_ns {
3330 match self.resolve_qpath(id, qself, path, ns, span, global_by_default, crate_lint) {
3331 // If defer_to_typeck, then resolution > no resolution,
3332 // otherwise full resolution > partial resolution > no resolution.
3333 Some(res) if res.unresolved_segments() == 0 || defer_to_typeck =>
3335 res => if fin_res.is_none() { fin_res = res },
3339 if primary_ns != MacroNS &&
3340 (self.macro_names.contains(&path[0].modern()) ||
3341 self.builtin_macros.get(&path[0].name).cloned()
3342 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang) ||
3343 self.macro_use_prelude.get(&path[0].name).cloned()
3344 .and_then(NameBinding::macro_kind) == Some(MacroKind::Bang)) {
3345 // Return some dummy definition, it's enough for error reporting.
3347 PathResolution::new(Def::Macro(DefId::local(CRATE_DEF_INDEX), MacroKind::Bang))
3353 /// Handles paths that may refer to associated items.
3354 fn resolve_qpath(&mut self,
3356 qself: Option<&QSelf>,
3360 global_by_default: bool,
3361 crate_lint: CrateLint)
3362 -> Option<PathResolution> {
3364 "resolve_qpath(id={:?}, qself={:?}, path={:?}, \
3365 ns={:?}, span={:?}, global_by_default={:?})",
3374 if let Some(qself) = qself {
3375 if qself.position == 0 {
3376 // This is a case like `<T>::B`, where there is no
3377 // trait to resolve. In that case, we leave the `B`
3378 // segment to be resolved by type-check.
3379 return Some(PathResolution::with_unresolved_segments(
3380 Def::Mod(DefId::local(CRATE_DEF_INDEX)), path.len()
3384 // Make sure `A::B` in `<T as A::B>::C` is a trait item.
3386 // Currently, `path` names the full item (`A::B::C`, in
3387 // our example). so we extract the prefix of that that is
3388 // the trait (the slice upto and including
3389 // `qself.position`). And then we recursively resolve that,
3390 // but with `qself` set to `None`.
3392 // However, setting `qself` to none (but not changing the
3393 // span) loses the information about where this path
3394 // *actually* appears, so for the purposes of the crate
3395 // lint we pass along information that this is the trait
3396 // name from a fully qualified path, and this also
3397 // contains the full span (the `CrateLint::QPathTrait`).
3398 let ns = if qself.position + 1 == path.len() { ns } else { TypeNS };
3399 let res = self.smart_resolve_path_fragment(
3402 &path[..qself.position + 1],
3404 PathSource::TraitItem(ns),
3405 CrateLint::QPathTrait {
3407 qpath_span: qself.path_span,
3411 // The remaining segments (the `C` in our example) will
3412 // have to be resolved by type-check, since that requires doing
3413 // trait resolution.
3414 return Some(PathResolution::with_unresolved_segments(
3415 res.base_def(), res.unresolved_segments() + path.len() - qself.position - 1
3419 let result = match self.resolve_path(
3427 PathResult::NonModule(path_res) => path_res,
3428 PathResult::Module(ModuleOrUniformRoot::Module(module)) if !module.is_normal() => {
3429 PathResolution::new(module.def().unwrap())
3431 // In `a(::assoc_item)*` `a` cannot be a module. If `a` does resolve to a module we
3432 // don't report an error right away, but try to fallback to a primitive type.
3433 // So, we are still able to successfully resolve something like
3435 // use std::u8; // bring module u8 in scope
3436 // fn f() -> u8 { // OK, resolves to primitive u8, not to std::u8
3437 // u8::max_value() // OK, resolves to associated function <u8>::max_value,
3438 // // not to non-existent std::u8::max_value
3441 // Such behavior is required for backward compatibility.
3442 // The same fallback is used when `a` resolves to nothing.
3443 PathResult::Module(ModuleOrUniformRoot::Module(_)) |
3444 PathResult::Failed(..)
3445 if (ns == TypeNS || path.len() > 1) &&
3446 self.primitive_type_table.primitive_types
3447 .contains_key(&path[0].name) => {
3448 let prim = self.primitive_type_table.primitive_types[&path[0].name];
3449 PathResolution::with_unresolved_segments(Def::PrimTy(prim), path.len() - 1)
3451 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3452 PathResolution::new(module.def().unwrap()),
3453 PathResult::Failed(span, msg, false) => {
3454 resolve_error(self, span, ResolutionError::FailedToResolve(&msg));
3455 err_path_resolution()
3457 PathResult::Module(ModuleOrUniformRoot::UniformRoot(_)) |
3458 PathResult::Failed(..) => return None,
3459 PathResult::Indeterminate => bug!("indetermined path result in resolve_qpath"),
3462 if path.len() > 1 && !global_by_default && result.base_def() != Def::Err &&
3463 path[0].name != keywords::CrateRoot.name() &&
3464 path[0].name != keywords::DollarCrate.name() {
3465 let unqualified_result = {
3466 match self.resolve_path(
3468 &[*path.last().unwrap()],
3474 PathResult::NonModule(path_res) => path_res.base_def(),
3475 PathResult::Module(ModuleOrUniformRoot::Module(module)) =>
3476 module.def().unwrap(),
3477 _ => return Some(result),
3480 if result.base_def() == unqualified_result {
3481 let lint = lint::builtin::UNUSED_QUALIFICATIONS;
3482 self.session.buffer_lint(lint, id, span, "unnecessary qualification")
3491 base_module: Option<ModuleOrUniformRoot<'a>>,
3493 opt_ns: Option<Namespace>, // `None` indicates a module path
3496 crate_lint: CrateLint,
3497 ) -> PathResult<'a> {
3498 let parent_scope = ParentScope { module: self.current_module, ..self.dummy_parent_scope() };
3499 self.resolve_path_with_parent_scope(base_module, path, opt_ns, &parent_scope,
3500 record_used, path_span, crate_lint)
3503 fn resolve_path_with_parent_scope(
3505 base_module: Option<ModuleOrUniformRoot<'a>>,
3507 opt_ns: Option<Namespace>, // `None` indicates a module path
3508 parent_scope: &ParentScope<'a>,
3511 crate_lint: CrateLint,
3512 ) -> PathResult<'a> {
3513 let mut module = base_module;
3514 let mut allow_super = true;
3515 let mut second_binding = None;
3516 self.current_module = parent_scope.module;
3519 "resolve_path(path={:?}, opt_ns={:?}, record_used={:?}, \
3520 path_span={:?}, crate_lint={:?})",
3528 for (i, &ident) in path.iter().enumerate() {
3529 debug!("resolve_path ident {} {:?}", i, ident);
3530 let is_last = i == path.len() - 1;
3531 let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
3532 let name = ident.name;
3534 allow_super &= ns == TypeNS &&
3535 (name == keywords::SelfValue.name() ||
3536 name == keywords::Super.name());
3539 if allow_super && name == keywords::Super.name() {
3540 let mut ctxt = ident.span.ctxt().modern();
3541 let self_module = match i {
3542 0 => Some(self.resolve_self(&mut ctxt, self.current_module)),
3544 Some(ModuleOrUniformRoot::Module(module)) => Some(module),
3548 if let Some(self_module) = self_module {
3549 if let Some(parent) = self_module.parent {
3550 module = Some(ModuleOrUniformRoot::Module(
3551 self.resolve_self(&mut ctxt, parent)));
3555 let msg = "There are too many initial `super`s.".to_string();
3556 return PathResult::Failed(ident.span, msg, false);
3559 if name == keywords::SelfValue.name() {
3560 let mut ctxt = ident.span.ctxt().modern();
3561 module = Some(ModuleOrUniformRoot::Module(
3562 self.resolve_self(&mut ctxt, self.current_module)));
3565 if name == keywords::Extern.name() ||
3566 name == keywords::CrateRoot.name() &&
3567 self.session.rust_2018() {
3568 module = Some(ModuleOrUniformRoot::UniformRoot(name));
3571 if name == keywords::CrateRoot.name() ||
3572 name == keywords::Crate.name() ||
3573 name == keywords::DollarCrate.name() {
3574 // `::a::b`, `crate::a::b` or `$crate::a::b`
3575 module = Some(ModuleOrUniformRoot::Module(
3576 self.resolve_crate_root(ident)));
3582 // Report special messages for path segment keywords in wrong positions.
3583 if ident.is_path_segment_keyword() && i != 0 {
3584 let name_str = if name == keywords::CrateRoot.name() {
3585 "crate root".to_string()
3587 format!("`{}`", name)
3589 let msg = if i == 1 && path[0].name == keywords::CrateRoot.name() {
3590 format!("global paths cannot start with {}", name_str)
3592 format!("{} in paths can only be used in start position", name_str)
3594 return PathResult::Failed(ident.span, msg, false);
3597 let binding = if let Some(module) = module {
3598 self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
3599 } else if opt_ns == Some(MacroNS) {
3600 assert!(ns == TypeNS);
3601 self.resolve_lexical_macro_path_segment(ident, ns, None, parent_scope, record_used,
3602 record_used, path_span).map(|(b, _)| b)
3604 let record_used_id =
3605 if record_used { crate_lint.node_id().or(Some(CRATE_NODE_ID)) } else { None };
3606 match self.resolve_ident_in_lexical_scope(ident, ns, record_used_id, path_span) {
3607 // we found a locally-imported or available item/module
3608 Some(LexicalScopeBinding::Item(binding)) => Ok(binding),
3609 // we found a local variable or type param
3610 Some(LexicalScopeBinding::Def(def))
3611 if opt_ns == Some(TypeNS) || opt_ns == Some(ValueNS) => {
3612 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3616 _ => Err(if record_used { Determined } else { Undetermined }),
3623 second_binding = Some(binding);
3625 let def = binding.def();
3626 let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(def);
3627 if let Some(next_module) = binding.module() {
3628 module = Some(ModuleOrUniformRoot::Module(next_module));
3629 } else if def == Def::ToolMod && i + 1 != path.len() {
3630 let def = Def::NonMacroAttr(NonMacroAttrKind::Tool);
3631 return PathResult::NonModule(PathResolution::new(def));
3632 } else if def == Def::Err {
3633 return PathResult::NonModule(err_path_resolution());
3634 } else if opt_ns.is_some() && (is_last || maybe_assoc) {
3635 self.lint_if_path_starts_with_module(
3641 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3642 def, path.len() - i - 1
3645 return PathResult::Failed(ident.span,
3646 format!("Not a module `{}`", ident),
3650 Err(Undetermined) => return PathResult::Indeterminate,
3651 Err(Determined) => {
3652 if let Some(ModuleOrUniformRoot::Module(module)) = module {
3653 if opt_ns.is_some() && !module.is_normal() {
3654 return PathResult::NonModule(PathResolution::with_unresolved_segments(
3655 module.def().unwrap(), path.len() - i
3659 let module_def = match module {
3660 Some(ModuleOrUniformRoot::Module(module)) => module.def(),
3663 let msg = if module_def == self.graph_root.def() {
3664 let is_mod = |def| match def { Def::Mod(..) => true, _ => false };
3665 let mut candidates =
3666 self.lookup_import_candidates(name, TypeNS, is_mod);
3667 candidates.sort_by_cached_key(|c| {
3668 (c.path.segments.len(), c.path.to_string())
3670 if let Some(candidate) = candidates.get(0) {
3671 format!("Did you mean `{}`?", candidate.path)
3673 format!("Maybe a missing `extern crate {};`?", ident)
3676 format!("Use of undeclared type or module `{}`", ident)
3678 format!("Could not find `{}` in `{}`", ident, path[i - 1])
3680 return PathResult::Failed(ident.span, msg, is_last);
3685 self.lint_if_path_starts_with_module(crate_lint, path, path_span, second_binding);
3687 PathResult::Module(module.unwrap_or_else(|| {
3688 span_bug!(path_span, "resolve_path: empty(?) path {:?} has no module", path);
3693 fn lint_if_path_starts_with_module(
3695 crate_lint: CrateLint,
3698 second_binding: Option<&NameBinding>,
3700 // In the 2018 edition this lint is a hard error, so nothing to do
3701 if self.session.rust_2018() {
3705 let (diag_id, diag_span) = match crate_lint {
3706 CrateLint::No => return,
3707 CrateLint::SimplePath(id) => (id, path_span),
3708 CrateLint::UsePath { root_id, root_span } => (root_id, root_span),
3709 CrateLint::QPathTrait { qpath_id, qpath_span } => (qpath_id, qpath_span),
3712 let first_name = match path.get(0) {
3713 Some(ident) => ident.name,
3717 // We're only interested in `use` paths which should start with
3718 // `{{root}}` or `extern` currently.
3719 if first_name != keywords::Extern.name() && first_name != keywords::CrateRoot.name() {
3724 // If this import looks like `crate::...` it's already good
3725 Some(ident) if ident.name == keywords::Crate.name() => return,
3726 // Otherwise go below to see if it's an extern crate
3728 // If the path has length one (and it's `CrateRoot` most likely)
3729 // then we don't know whether we're gonna be importing a crate or an
3730 // item in our crate. Defer this lint to elsewhere
3734 // If the first element of our path was actually resolved to an
3735 // `ExternCrate` (also used for `crate::...`) then no need to issue a
3736 // warning, this looks all good!
3737 if let Some(binding) = second_binding {
3738 if let NameBindingKind::Import { directive: d, .. } = binding.kind {
3739 // Careful: we still want to rewrite paths from
3740 // renamed extern crates.
3741 if let ImportDirectiveSubclass::ExternCrate(None) = d.subclass {
3747 let diag = lint::builtin::BuiltinLintDiagnostics
3748 ::AbsPathWithModule(diag_span);
3749 self.session.buffer_lint_with_diagnostic(
3750 lint::builtin::ABSOLUTE_PATHS_NOT_STARTING_WITH_CRATE,
3752 "absolute paths must start with `self`, `super`, \
3753 `crate`, or an external crate name in the 2018 edition",
3757 // Resolve a local definition, potentially adjusting for closures.
3758 fn adjust_local_def(&mut self,
3763 span: Span) -> Def {
3764 let ribs = &self.ribs[ns][rib_index + 1..];
3766 // An invalid forward use of a type parameter from a previous default.
3767 if let ForwardTyParamBanRibKind = self.ribs[ns][rib_index].kind {
3769 resolve_error(self, span, ResolutionError::ForwardDeclaredTyParam);
3771 assert_eq!(def, Def::Err);
3777 span_bug!(span, "unexpected {:?} in bindings", def)
3779 Def::Local(node_id) => {
3782 NormalRibKind | ModuleRibKind(..) | MacroDefinition(..) |
3783 ForwardTyParamBanRibKind => {
3784 // Nothing to do. Continue.
3786 ClosureRibKind(function_id) => {
3789 let seen = self.freevars_seen
3792 if let Some(&index) = seen.get(&node_id) {
3793 def = Def::Upvar(node_id, index, function_id);
3796 let vec = self.freevars
3799 let depth = vec.len();
3800 def = Def::Upvar(node_id, depth, function_id);
3807 seen.insert(node_id, depth);
3810 ItemRibKind | TraitOrImplItemRibKind => {
3811 // This was an attempt to access an upvar inside a
3812 // named function item. This is not allowed, so we
3815 resolve_error(self, span,
3816 ResolutionError::CannotCaptureDynamicEnvironmentInFnItem);
3820 ConstantItemRibKind => {
3821 // Still doesn't deal with upvars
3823 resolve_error(self, span,
3824 ResolutionError::AttemptToUseNonConstantValueInConstant);
3831 Def::TyParam(..) | Def::SelfTy(..) => {
3834 NormalRibKind | TraitOrImplItemRibKind | ClosureRibKind(..) |
3835 ModuleRibKind(..) | MacroDefinition(..) | ForwardTyParamBanRibKind |
3836 ConstantItemRibKind => {
3837 // Nothing to do. Continue.
3840 // This was an attempt to use a type parameter outside
3843 resolve_error(self, span,
3844 ResolutionError::TypeParametersFromOuterFunction(def));
3856 fn lookup_assoc_candidate<FilterFn>(&mut self,
3859 filter_fn: FilterFn)
3860 -> Option<AssocSuggestion>
3861 where FilterFn: Fn(Def) -> bool
3863 fn extract_node_id(t: &Ty) -> Option<NodeId> {
3865 TyKind::Path(None, _) => Some(t.id),
3866 TyKind::Rptr(_, ref mut_ty) => extract_node_id(&mut_ty.ty),
3867 // This doesn't handle the remaining `Ty` variants as they are not
3868 // that commonly the self_type, it might be interesting to provide
3869 // support for those in future.
3874 // Fields are generally expected in the same contexts as locals.
3875 if filter_fn(Def::Local(ast::DUMMY_NODE_ID)) {
3876 if let Some(node_id) = self.current_self_type.as_ref().and_then(extract_node_id) {
3877 // Look for a field with the same name in the current self_type.
3878 if let Some(resolution) = self.def_map.get(&node_id) {
3879 match resolution.base_def() {
3880 Def::Struct(did) | Def::Union(did)
3881 if resolution.unresolved_segments() == 0 => {
3882 if let Some(field_names) = self.field_names.get(&did) {
3883 if field_names.iter().any(|&field_name| ident.name == field_name) {
3884 return Some(AssocSuggestion::Field);
3894 // Look for associated items in the current trait.
3895 if let Some((module, _)) = self.current_trait_ref {
3896 if let Ok(binding) = self.resolve_ident_in_module(
3897 ModuleOrUniformRoot::Module(module),
3903 let def = binding.def();
3905 return Some(if self.has_self.contains(&def.def_id()) {
3906 AssocSuggestion::MethodWithSelf
3908 AssocSuggestion::AssocItem
3917 fn lookup_typo_candidate<FilterFn>(&mut self,
3920 filter_fn: FilterFn,
3923 where FilterFn: Fn(Def) -> bool
3925 let add_module_candidates = |module: Module, names: &mut Vec<Name>| {
3926 for (&(ident, _), resolution) in module.resolutions.borrow().iter() {
3927 if let Some(binding) = resolution.borrow().binding {
3928 if filter_fn(binding.def()) {
3929 names.push(ident.name);
3935 let mut names = Vec::new();
3936 if path.len() == 1 {
3937 // Search in lexical scope.
3938 // Walk backwards up the ribs in scope and collect candidates.
3939 for rib in self.ribs[ns].iter().rev() {
3940 // Locals and type parameters
3941 for (ident, def) in &rib.bindings {
3942 if filter_fn(*def) {
3943 names.push(ident.name);
3947 if let ModuleRibKind(module) = rib.kind {
3948 // Items from this module
3949 add_module_candidates(module, &mut names);
3951 if let ModuleKind::Block(..) = module.kind {
3952 // We can see through blocks
3954 // Items from the prelude
3955 if !module.no_implicit_prelude {
3956 names.extend(self.extern_prelude.iter().cloned());
3957 if let Some(prelude) = self.prelude {
3958 add_module_candidates(prelude, &mut names);
3965 // Add primitive types to the mix
3966 if filter_fn(Def::PrimTy(Bool)) {
3968 self.primitive_type_table.primitive_types.iter().map(|(name, _)| name)
3972 // Search in module.
3973 let mod_path = &path[..path.len() - 1];
3974 if let PathResult::Module(module) = self.resolve_path(None, mod_path, Some(TypeNS),
3975 false, span, CrateLint::No) {
3976 if let ModuleOrUniformRoot::Module(module) = module {
3977 add_module_candidates(module, &mut names);
3982 let name = path[path.len() - 1].name;
3983 // Make sure error reporting is deterministic.
3984 names.sort_by_cached_key(|name| name.as_str());
3985 match find_best_match_for_name(names.iter(), &name.as_str(), None) {
3986 Some(found) if found != name => Some(found),
3991 fn with_resolved_label<F>(&mut self, label: Option<Label>, id: NodeId, f: F)
3992 where F: FnOnce(&mut Resolver)
3994 if let Some(label) = label {
3995 self.unused_labels.insert(id, label.ident.span);
3996 let def = Def::Label(id);
3997 self.with_label_rib(|this| {
3998 let ident = label.ident.modern_and_legacy();
3999 this.label_ribs.last_mut().unwrap().bindings.insert(ident, def);
4007 fn resolve_labeled_block(&mut self, label: Option<Label>, id: NodeId, block: &Block) {
4008 self.with_resolved_label(label, id, |this| this.visit_block(block));
4011 fn resolve_expr(&mut self, expr: &Expr, parent: Option<&Expr>) {
4012 // First, record candidate traits for this expression if it could
4013 // result in the invocation of a method call.
4015 self.record_candidate_traits_for_expr_if_necessary(expr);
4017 // Next, resolve the node.
4019 ExprKind::Path(ref qself, ref path) => {
4020 self.smart_resolve_path(expr.id, qself.as_ref(), path, PathSource::Expr(parent));
4021 visit::walk_expr(self, expr);
4024 ExprKind::Struct(ref path, ..) => {
4025 self.smart_resolve_path(expr.id, None, path, PathSource::Struct);
4026 visit::walk_expr(self, expr);
4029 ExprKind::Break(Some(label), _) | ExprKind::Continue(Some(label)) => {
4030 let def = self.search_label(label.ident, |rib, ident| {
4031 rib.bindings.get(&ident.modern_and_legacy()).cloned()
4035 // Search again for close matches...
4036 // Picks the first label that is "close enough", which is not necessarily
4037 // the closest match
4038 let close_match = self.search_label(label.ident, |rib, ident| {
4039 let names = rib.bindings.iter().map(|(id, _)| &id.name);
4040 find_best_match_for_name(names, &*ident.as_str(), None)
4042 self.record_def(expr.id, err_path_resolution());
4045 ResolutionError::UndeclaredLabel(&label.ident.as_str(),
4048 Some(Def::Label(id)) => {
4049 // Since this def is a label, it is never read.
4050 self.record_def(expr.id, PathResolution::new(Def::Label(id)));
4051 self.unused_labels.remove(&id);
4054 span_bug!(expr.span, "label wasn't mapped to a label def!");
4058 // visit `break` argument if any
4059 visit::walk_expr(self, expr);
4062 ExprKind::IfLet(ref pats, ref subexpression, ref if_block, ref optional_else) => {
4063 self.visit_expr(subexpression);
4065 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4066 let mut bindings_list = FxHashMap();
4068 self.resolve_pattern(pat, PatternSource::IfLet, &mut bindings_list);
4070 // This has to happen *after* we determine which pat_idents are variants
4071 self.check_consistent_bindings(pats);
4072 self.visit_block(if_block);
4073 self.ribs[ValueNS].pop();
4075 optional_else.as_ref().map(|expr| self.visit_expr(expr));
4078 ExprKind::Loop(ref block, label) => self.resolve_labeled_block(label, expr.id, &block),
4080 ExprKind::While(ref subexpression, ref block, label) => {
4081 self.with_resolved_label(label, expr.id, |this| {
4082 this.visit_expr(subexpression);
4083 this.visit_block(block);
4087 ExprKind::WhileLet(ref pats, ref subexpression, ref block, label) => {
4088 self.with_resolved_label(label, expr.id, |this| {
4089 this.visit_expr(subexpression);
4090 this.ribs[ValueNS].push(Rib::new(NormalRibKind));
4091 let mut bindings_list = FxHashMap();
4093 this.resolve_pattern(pat, PatternSource::WhileLet, &mut bindings_list);
4095 // This has to happen *after* we determine which pat_idents are variants
4096 this.check_consistent_bindings(pats);
4097 this.visit_block(block);
4098 this.ribs[ValueNS].pop();
4102 ExprKind::ForLoop(ref pattern, ref subexpression, ref block, label) => {
4103 self.visit_expr(subexpression);
4104 self.ribs[ValueNS].push(Rib::new(NormalRibKind));
4105 self.resolve_pattern(pattern, PatternSource::For, &mut FxHashMap());
4107 self.resolve_labeled_block(label, expr.id, block);
4109 self.ribs[ValueNS].pop();
4112 ExprKind::Block(ref block, label) => self.resolve_labeled_block(label, block.id, block),
4114 // Equivalent to `visit::walk_expr` + passing some context to children.
4115 ExprKind::Field(ref subexpression, _) => {
4116 self.resolve_expr(subexpression, Some(expr));
4118 ExprKind::MethodCall(ref segment, ref arguments) => {
4119 let mut arguments = arguments.iter();
4120 self.resolve_expr(arguments.next().unwrap(), Some(expr));
4121 for argument in arguments {
4122 self.resolve_expr(argument, None);
4124 self.visit_path_segment(expr.span, segment);
4127 ExprKind::Call(ref callee, ref arguments) => {
4128 self.resolve_expr(callee, Some(expr));
4129 for argument in arguments {
4130 self.resolve_expr(argument, None);
4133 ExprKind::Type(ref type_expr, _) => {
4134 self.current_type_ascription.push(type_expr.span);
4135 visit::walk_expr(self, expr);
4136 self.current_type_ascription.pop();
4138 // Resolve the body of async exprs inside the async closure to which they desugar
4139 ExprKind::Async(_, async_closure_id, ref block) => {
4140 let rib_kind = ClosureRibKind(async_closure_id);
4141 self.ribs[ValueNS].push(Rib::new(rib_kind));
4142 self.label_ribs.push(Rib::new(rib_kind));
4143 self.visit_block(&block);
4144 self.label_ribs.pop();
4145 self.ribs[ValueNS].pop();
4147 // `async |x| ...` gets desugared to `|x| future_from_generator(|| ...)`, so we need to
4148 // resolve the arguments within the proper scopes so that usages of them inside the
4149 // closure are detected as upvars rather than normal closure arg usages.
4151 _, IsAsync::Async { closure_id: inner_closure_id, .. }, _,
4152 ref fn_decl, ref body, _span,
4154 let rib_kind = ClosureRibKind(expr.id);
4155 self.ribs[ValueNS].push(Rib::new(rib_kind));
4156 self.label_ribs.push(Rib::new(rib_kind));
4157 // Resolve arguments:
4158 let mut bindings_list = FxHashMap();
4159 for argument in &fn_decl.inputs {
4160 self.resolve_pattern(&argument.pat, PatternSource::FnParam, &mut bindings_list);
4161 self.visit_ty(&argument.ty);
4163 // No need to resolve return type-- the outer closure return type is
4164 // FunctionRetTy::Default
4166 // Now resolve the inner closure
4168 let rib_kind = ClosureRibKind(inner_closure_id);
4169 self.ribs[ValueNS].push(Rib::new(rib_kind));
4170 self.label_ribs.push(Rib::new(rib_kind));
4171 // No need to resolve arguments: the inner closure has none.
4172 // Resolve the return type:
4173 visit::walk_fn_ret_ty(self, &fn_decl.output);
4175 self.visit_expr(body);
4176 self.label_ribs.pop();
4177 self.ribs[ValueNS].pop();
4179 self.label_ribs.pop();
4180 self.ribs[ValueNS].pop();
4183 visit::walk_expr(self, expr);
4188 fn record_candidate_traits_for_expr_if_necessary(&mut self, expr: &Expr) {
4190 ExprKind::Field(_, ident) => {
4191 // FIXME(#6890): Even though you can't treat a method like a
4192 // field, we need to add any trait methods we find that match
4193 // the field name so that we can do some nice error reporting
4194 // later on in typeck.
4195 let traits = self.get_traits_containing_item(ident, ValueNS);
4196 self.trait_map.insert(expr.id, traits);
4198 ExprKind::MethodCall(ref segment, ..) => {
4199 debug!("(recording candidate traits for expr) recording traits for {}",
4201 let traits = self.get_traits_containing_item(segment.ident, ValueNS);
4202 self.trait_map.insert(expr.id, traits);
4210 fn get_traits_containing_item(&mut self, mut ident: Ident, ns: Namespace)
4211 -> Vec<TraitCandidate> {
4212 debug!("(getting traits containing item) looking for '{}'", ident.name);
4214 let mut found_traits = Vec::new();
4215 // Look for the current trait.
4216 if let Some((module, _)) = self.current_trait_ref {
4217 if self.resolve_ident_in_module(
4218 ModuleOrUniformRoot::Module(module),
4224 let def_id = module.def_id().unwrap();
4225 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
4229 ident.span = ident.span.modern();
4230 let mut search_module = self.current_module;
4232 self.get_traits_in_module_containing_item(ident, ns, search_module, &mut found_traits);
4233 search_module = unwrap_or!(
4234 self.hygienic_lexical_parent(search_module, &mut ident.span), break
4238 if let Some(prelude) = self.prelude {
4239 if !search_module.no_implicit_prelude {
4240 self.get_traits_in_module_containing_item(ident, ns, prelude, &mut found_traits);
4247 fn get_traits_in_module_containing_item(&mut self,
4251 found_traits: &mut Vec<TraitCandidate>) {
4252 assert!(ns == TypeNS || ns == ValueNS);
4253 let mut traits = module.traits.borrow_mut();
4254 if traits.is_none() {
4255 let mut collected_traits = Vec::new();
4256 module.for_each_child(|name, ns, binding| {
4257 if ns != TypeNS { return }
4258 if let Def::Trait(_) = binding.def() {
4259 collected_traits.push((name, binding));
4262 *traits = Some(collected_traits.into_boxed_slice());
4265 for &(trait_name, binding) in traits.as_ref().unwrap().iter() {
4266 let module = binding.module().unwrap();
4267 let mut ident = ident;
4268 if ident.span.glob_adjust(module.expansion, binding.span.ctxt().modern()).is_none() {
4271 if self.resolve_ident_in_module_unadjusted(
4272 ModuleOrUniformRoot::Module(module),
4279 let import_id = match binding.kind {
4280 NameBindingKind::Import { directive, .. } => {
4281 self.maybe_unused_trait_imports.insert(directive.id);
4282 self.add_to_glob_map(directive.id, trait_name);
4287 let trait_def_id = module.def_id().unwrap();
4288 found_traits.push(TraitCandidate { def_id: trait_def_id, import_id: import_id });
4293 fn lookup_import_candidates_from_module<FilterFn>(&mut self,
4295 namespace: Namespace,
4296 start_module: &'a ModuleData<'a>,
4298 filter_fn: FilterFn)
4299 -> Vec<ImportSuggestion>
4300 where FilterFn: Fn(Def) -> bool
4302 let mut candidates = Vec::new();
4303 let mut worklist = Vec::new();
4304 let mut seen_modules = FxHashSet();
4305 let not_local_module = crate_name != keywords::Crate.ident();
4306 worklist.push((start_module, Vec::<ast::PathSegment>::new(), not_local_module));
4308 while let Some((in_module,
4310 in_module_is_extern)) = worklist.pop() {
4311 self.populate_module_if_necessary(in_module);
4313 // We have to visit module children in deterministic order to avoid
4314 // instabilities in reported imports (#43552).
4315 in_module.for_each_child_stable(|ident, ns, name_binding| {
4316 // avoid imports entirely
4317 if name_binding.is_import() && !name_binding.is_extern_crate() { return; }
4318 // avoid non-importable candidates as well
4319 if !name_binding.is_importable() { return; }
4321 // collect results based on the filter function
4322 if ident.name == lookup_name && ns == namespace {
4323 if filter_fn(name_binding.def()) {
4325 let mut segms = path_segments.clone();
4326 if self.session.rust_2018() {
4327 // crate-local absolute paths start with `crate::` in edition 2018
4328 // FIXME: may also be stabilized for Rust 2015 (Issues #45477, #44660)
4330 0, ast::PathSegment::from_ident(crate_name)
4334 segms.push(ast::PathSegment::from_ident(ident));
4336 span: name_binding.span,
4339 // the entity is accessible in the following cases:
4340 // 1. if it's defined in the same crate, it's always
4341 // accessible (since private entities can be made public)
4342 // 2. if it's defined in another crate, it's accessible
4343 // only if both the module is public and the entity is
4344 // declared as public (due to pruning, we don't explore
4345 // outside crate private modules => no need to check this)
4346 if !in_module_is_extern || name_binding.vis == ty::Visibility::Public {
4347 candidates.push(ImportSuggestion { path: path });
4352 // collect submodules to explore
4353 if let Some(module) = name_binding.module() {
4355 let mut path_segments = path_segments.clone();
4356 path_segments.push(ast::PathSegment::from_ident(ident));
4358 let is_extern_crate_that_also_appears_in_prelude =
4359 name_binding.is_extern_crate() &&
4360 self.session.rust_2018();
4362 let is_visible_to_user =
4363 !in_module_is_extern || name_binding.vis == ty::Visibility::Public;
4365 if !is_extern_crate_that_also_appears_in_prelude && is_visible_to_user {
4366 // add the module to the lookup
4367 let is_extern = in_module_is_extern || name_binding.is_extern_crate();
4368 if seen_modules.insert(module.def_id().unwrap()) {
4369 worklist.push((module, path_segments, is_extern));
4379 /// When name resolution fails, this method can be used to look up candidate
4380 /// entities with the expected name. It allows filtering them using the
4381 /// supplied predicate (which should be used to only accept the types of
4382 /// definitions expected e.g. traits). The lookup spans across all crates.
4384 /// NOTE: The method does not look into imports, but this is not a problem,
4385 /// since we report the definitions (thus, the de-aliased imports).
4386 fn lookup_import_candidates<FilterFn>(&mut self,
4388 namespace: Namespace,
4389 filter_fn: FilterFn)
4390 -> Vec<ImportSuggestion>
4391 where FilterFn: Fn(Def) -> bool
4393 let mut suggestions = vec![];
4396 self.lookup_import_candidates_from_module(
4397 lookup_name, namespace, self.graph_root, keywords::Crate.ident(), &filter_fn
4401 if self.session.rust_2018() {
4402 let extern_prelude_names = self.extern_prelude.clone();
4403 for &name in extern_prelude_names.iter() {
4404 let ident = Ident::with_empty_ctxt(name);
4405 match self.crate_loader.maybe_process_path_extern(name, ident.span) {
4407 let crate_root = self.get_module(DefId {
4409 index: CRATE_DEF_INDEX,
4411 self.populate_module_if_necessary(&crate_root);
4414 self.lookup_import_candidates_from_module(
4415 lookup_name, namespace, crate_root, ident, &filter_fn
4427 fn find_module(&mut self,
4429 -> Option<(Module<'a>, ImportSuggestion)>
4431 let mut result = None;
4432 let mut worklist = Vec::new();
4433 let mut seen_modules = FxHashSet();
4434 worklist.push((self.graph_root, Vec::new()));
4436 while let Some((in_module, path_segments)) = worklist.pop() {
4437 // abort if the module is already found
4438 if result.is_some() { break; }
4440 self.populate_module_if_necessary(in_module);
4442 in_module.for_each_child_stable(|ident, _, name_binding| {
4443 // abort if the module is already found or if name_binding is private external
4444 if result.is_some() || !name_binding.vis.is_visible_locally() {
4447 if let Some(module) = name_binding.module() {
4449 let mut path_segments = path_segments.clone();
4450 path_segments.push(ast::PathSegment::from_ident(ident));
4451 if module.def() == Some(module_def) {
4453 span: name_binding.span,
4454 segments: path_segments,
4456 result = Some((module, ImportSuggestion { path: path }));
4458 // add the module to the lookup
4459 if seen_modules.insert(module.def_id().unwrap()) {
4460 worklist.push((module, path_segments));
4470 fn collect_enum_variants(&mut self, enum_def: Def) -> Option<Vec<Path>> {
4471 if let Def::Enum(..) = enum_def {} else {
4472 panic!("Non-enum def passed to collect_enum_variants: {:?}", enum_def)
4475 self.find_module(enum_def).map(|(enum_module, enum_import_suggestion)| {
4476 self.populate_module_if_necessary(enum_module);
4478 let mut variants = Vec::new();
4479 enum_module.for_each_child_stable(|ident, _, name_binding| {
4480 if let Def::Variant(..) = name_binding.def() {
4481 let mut segms = enum_import_suggestion.path.segments.clone();
4482 segms.push(ast::PathSegment::from_ident(ident));
4483 variants.push(Path {
4484 span: name_binding.span,
4493 fn record_def(&mut self, node_id: NodeId, resolution: PathResolution) {
4494 debug!("(recording def) recording {:?} for {}", resolution, node_id);
4495 if let Some(prev_res) = self.def_map.insert(node_id, resolution) {
4496 panic!("path resolved multiple times ({:?} before, {:?} now)", prev_res, resolution);
4500 fn resolve_visibility(&mut self, vis: &ast::Visibility) -> ty::Visibility {
4502 ast::VisibilityKind::Public => ty::Visibility::Public,
4503 ast::VisibilityKind::Crate(..) => {
4504 ty::Visibility::Restricted(DefId::local(CRATE_DEF_INDEX))
4506 ast::VisibilityKind::Inherited => {
4507 ty::Visibility::Restricted(self.current_module.normal_ancestor_id)
4509 ast::VisibilityKind::Restricted { ref path, id, .. } => {
4510 // Visibilities are resolved as global by default, add starting root segment.
4511 let segments = path.make_root().iter().chain(path.segments.iter())
4512 .map(|seg| seg.ident)
4513 .collect::<Vec<_>>();
4514 let def = self.smart_resolve_path_fragment(
4519 PathSource::Visibility,
4520 CrateLint::SimplePath(id),
4522 if def == Def::Err {
4523 ty::Visibility::Public
4525 let vis = ty::Visibility::Restricted(def.def_id());
4526 if self.is_accessible(vis) {
4529 self.session.span_err(path.span, "visibilities can only be restricted \
4530 to ancestor modules");
4531 ty::Visibility::Public
4538 fn is_accessible(&self, vis: ty::Visibility) -> bool {
4539 vis.is_accessible_from(self.current_module.normal_ancestor_id, self)
4542 fn is_accessible_from(&self, vis: ty::Visibility, module: Module<'a>) -> bool {
4543 vis.is_accessible_from(module.normal_ancestor_id, self)
4546 fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
4547 let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
4549 format!("`{}` could refer to the name {} here", ident, participle(b1.is_import()));
4551 format!("`{}` could also refer to the name {} here", ident, participle(b2.is_import()));
4552 let note = if b1.expansion != Mark::root() {
4553 Some(if let Def::Macro(..) = b1.def() {
4554 format!("macro-expanded {} do not shadow",
4555 if b1.is_import() { "macro imports" } else { "macros" })
4557 format!("macro-expanded {} do not shadow when used in a macro invocation path",
4558 if b1.is_import() { "imports" } else { "items" })
4560 } else if b1.is_glob_import() {
4561 Some(format!("consider adding an explicit import of `{}` to disambiguate", ident))
4566 let mut err = struct_span_err!(self.session, ident.span, E0659, "`{}` is ambiguous", ident);
4567 err.span_label(ident.span, "ambiguous name");
4568 err.span_note(b1.span, &msg1);
4570 Def::Macro(..) if b2.span.is_dummy() =>
4571 err.note(&format!("`{}` is also a builtin macro", ident)),
4572 _ => err.span_note(b2.span, &msg2),
4574 if let Some(note) = note {
4580 fn report_errors(&mut self, krate: &Crate) {
4581 self.report_with_use_injections(krate);
4582 let mut reported_spans = FxHashSet();
4584 for &(span_use, span_def) in &self.macro_expanded_macro_export_errors {
4585 let msg = "macro-expanded `macro_export` macros from the current crate \
4586 cannot be referred to by absolute paths";
4587 self.session.buffer_lint_with_diagnostic(
4588 lint::builtin::MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
4589 CRATE_NODE_ID, span_use, msg,
4590 lint::builtin::BuiltinLintDiagnostics::
4591 MacroExpandedMacroExportsAccessedByAbsolutePaths(span_def),
4595 for &AmbiguityError { ident, b1, b2 } in &self.ambiguity_errors {
4596 if reported_spans.insert(ident.span) {
4597 self.report_ambiguity_error(ident, b1, b2);
4601 for &PrivacyError(span, name, binding) in &self.privacy_errors {
4602 if !reported_spans.insert(span) { continue }
4603 span_err!(self.session, span, E0603, "{} `{}` is private", binding.descr(), name);
4607 fn report_with_use_injections(&mut self, krate: &Crate) {
4608 for UseError { mut err, candidates, node_id, better } in self.use_injections.drain(..) {
4609 let (span, found_use) = UsePlacementFinder::check(krate, node_id);
4610 if !candidates.is_empty() {
4611 show_candidates(&mut err, span, &candidates, better, found_use);
4617 fn report_conflict<'b>(&mut self,
4621 new_binding: &NameBinding<'b>,
4622 old_binding: &NameBinding<'b>) {
4623 // Error on the second of two conflicting names
4624 if old_binding.span.lo() > new_binding.span.lo() {
4625 return self.report_conflict(parent, ident, ns, old_binding, new_binding);
4628 let container = match parent.kind {
4629 ModuleKind::Def(Def::Mod(_), _) => "module",
4630 ModuleKind::Def(Def::Trait(_), _) => "trait",
4631 ModuleKind::Block(..) => "block",
4635 let old_noun = match old_binding.is_import() {
4637 false => "definition",
4640 let new_participle = match new_binding.is_import() {
4645 let (name, span) = (ident.name, self.session.source_map().def_span(new_binding.span));
4647 if let Some(s) = self.name_already_seen.get(&name) {
4653 let old_kind = match (ns, old_binding.module()) {
4654 (ValueNS, _) => "value",
4655 (MacroNS, _) => "macro",
4656 (TypeNS, _) if old_binding.is_extern_crate() => "extern crate",
4657 (TypeNS, Some(module)) if module.is_normal() => "module",
4658 (TypeNS, Some(module)) if module.is_trait() => "trait",
4659 (TypeNS, _) => "type",
4662 let msg = format!("the name `{}` is defined multiple times", name);
4664 let mut err = match (old_binding.is_extern_crate(), new_binding.is_extern_crate()) {
4665 (true, true) => struct_span_err!(self.session, span, E0259, "{}", msg),
4666 (true, _) | (_, true) => match new_binding.is_import() && old_binding.is_import() {
4667 true => struct_span_err!(self.session, span, E0254, "{}", msg),
4668 false => struct_span_err!(self.session, span, E0260, "{}", msg),
4670 _ => match (old_binding.is_import(), new_binding.is_import()) {
4671 (false, false) => struct_span_err!(self.session, span, E0428, "{}", msg),
4672 (true, true) => struct_span_err!(self.session, span, E0252, "{}", msg),
4673 _ => struct_span_err!(self.session, span, E0255, "{}", msg),
4677 err.note(&format!("`{}` must be defined only once in the {} namespace of this {}",
4682 err.span_label(span, format!("`{}` re{} here", name, new_participle));
4683 if !old_binding.span.is_dummy() {
4684 err.span_label(self.session.source_map().def_span(old_binding.span),
4685 format!("previous {} of the {} `{}` here", old_noun, old_kind, name));
4688 // See https://github.com/rust-lang/rust/issues/32354
4689 if old_binding.is_import() || new_binding.is_import() {
4690 let binding = if new_binding.is_import() && !new_binding.span.is_dummy() {
4696 let cm = self.session.source_map();
4697 let rename_msg = "You can use `as` to change the binding name of the import";
4699 if let (Ok(snippet), false) = (cm.span_to_snippet(binding.span),
4700 binding.is_renamed_extern_crate()) {
4701 let suggested_name = if name.as_str().chars().next().unwrap().is_uppercase() {
4702 format!("Other{}", name)
4704 format!("other_{}", name)
4707 err.span_suggestion_with_applicability(
4710 if snippet.ends_with(';') {
4711 format!("{} as {};", &snippet[..snippet.len() - 1], suggested_name)
4713 format!("{} as {}", snippet, suggested_name)
4715 Applicability::MachineApplicable,
4718 err.span_label(binding.span, rename_msg);
4723 self.name_already_seen.insert(name, span);
4727 fn is_self_type(path: &[Ident], namespace: Namespace) -> bool {
4728 namespace == TypeNS && path.len() == 1 && path[0].name == keywords::SelfType.name()
4731 fn is_self_value(path: &[Ident], namespace: Namespace) -> bool {
4732 namespace == ValueNS && path.len() == 1 && path[0].name == keywords::SelfValue.name()
4735 fn names_to_string(idents: &[Ident]) -> String {
4736 let mut result = String::new();
4737 for (i, ident) in idents.iter()
4738 .filter(|ident| ident.name != keywords::CrateRoot.name())
4741 result.push_str("::");
4743 result.push_str(&ident.as_str());
4748 fn path_names_to_string(path: &Path) -> String {
4749 names_to_string(&path.segments.iter()
4750 .map(|seg| seg.ident)
4751 .collect::<Vec<_>>())
4754 /// Get the path for an enum and the variant from an `ImportSuggestion` for an enum variant.
4755 fn import_candidate_to_paths(suggestion: &ImportSuggestion) -> (Span, String, String) {
4756 let variant_path = &suggestion.path;
4757 let variant_path_string = path_names_to_string(variant_path);
4759 let path_len = suggestion.path.segments.len();
4760 let enum_path = ast::Path {
4761 span: suggestion.path.span,
4762 segments: suggestion.path.segments[0..path_len - 1].to_vec(),
4764 let enum_path_string = path_names_to_string(&enum_path);
4766 (suggestion.path.span, variant_path_string, enum_path_string)
4770 /// When an entity with a given name is not available in scope, we search for
4771 /// entities with that name in all crates. This method allows outputting the
4772 /// results of this search in a programmer-friendly way
4773 fn show_candidates(err: &mut DiagnosticBuilder,
4774 // This is `None` if all placement locations are inside expansions
4776 candidates: &[ImportSuggestion],
4780 // we want consistent results across executions, but candidates are produced
4781 // by iterating through a hash map, so make sure they are ordered:
4782 let mut path_strings: Vec<_> =
4783 candidates.into_iter().map(|c| path_names_to_string(&c.path)).collect();
4784 path_strings.sort();
4786 let better = if better { "better " } else { "" };
4787 let msg_diff = match path_strings.len() {
4788 1 => " is found in another module, you can import it",
4789 _ => "s are found in other modules, you can import them",
4791 let msg = format!("possible {}candidate{} into scope", better, msg_diff);
4793 if let Some(span) = span {
4794 for candidate in &mut path_strings {
4795 // produce an additional newline to separate the new use statement
4796 // from the directly following item.
4797 let additional_newline = if found_use {
4802 *candidate = format!("use {};\n{}", candidate, additional_newline);
4805 err.span_suggestions_with_applicability(
4809 Applicability::Unspecified,
4814 for candidate in path_strings {
4816 msg.push_str(&candidate);
4821 /// A somewhat inefficient routine to obtain the name of a module.
4822 fn module_to_string(module: Module) -> Option<String> {
4823 let mut names = Vec::new();
4825 fn collect_mod(names: &mut Vec<Ident>, module: Module) {
4826 if let ModuleKind::Def(_, name) = module.kind {
4827 if let Some(parent) = module.parent {
4828 names.push(Ident::with_empty_ctxt(name));
4829 collect_mod(names, parent);
4832 // danger, shouldn't be ident?
4833 names.push(Ident::from_str("<opaque>"));
4834 collect_mod(names, module.parent.unwrap());
4837 collect_mod(&mut names, module);
4839 if names.is_empty() {
4842 Some(names_to_string(&names.into_iter()
4844 .collect::<Vec<_>>()))
4847 fn err_path_resolution() -> PathResolution {
4848 PathResolution::new(Def::Err)
4851 #[derive(PartialEq,Copy, Clone)]
4852 pub enum MakeGlobMap {
4857 #[derive(Copy, Clone, Debug)]
4859 /// Do not issue the lint
4862 /// This lint applies to some random path like `impl ::foo::Bar`
4863 /// or whatever. In this case, we can take the span of that path.
4866 /// This lint comes from a `use` statement. In this case, what we
4867 /// care about really is the *root* `use` statement; e.g., if we
4868 /// have nested things like `use a::{b, c}`, we care about the
4870 UsePath { root_id: NodeId, root_span: Span },
4872 /// This is the "trait item" from a fully qualified path. For example,
4873 /// we might be resolving `X::Y::Z` from a path like `<T as X::Y>::Z`.
4874 /// The `path_span` is the span of the to the trait itself (`X::Y`).
4875 QPathTrait { qpath_id: NodeId, qpath_span: Span },
4879 fn node_id(&self) -> Option<NodeId> {
4881 CrateLint::No => None,
4882 CrateLint::SimplePath(id) |
4883 CrateLint::UsePath { root_id: id, .. } |
4884 CrateLint::QPathTrait { qpath_id: id, .. } => Some(id),
4889 __build_diagnostic_array! { librustc_resolve, DIAGNOSTICS }